diff --git a/examples/spines.rs b/examples/spines.rs
index 6720575fe..934ec6696 100644
--- a/examples/spines.rs
+++ b/examples/spines.rs
@@ -65,9 +65,9 @@ fn main() {
                         .probe_with(&mut probe);
                 },
                 "flat" => {
-                    use differential_dataflow::trace::implementations::ord_neu::FlatKeySpine;
-                    let data = data.arrange::<FlatKeySpine<String,_,isize,_>>();
-                    let keys = keys.arrange::<FlatKeySpine<String,_,isize,_>>();
+                    use differential_dataflow::trace::implementations::ord_neu::FlatKeySpineDefault;
+                    let data = data.arrange::<FlatKeySpineDefault<String,usize,isize, _>>();
+                    let keys = keys.arrange::<FlatKeySpineDefault<String,usize,isize,_>>();
                     keys.join_core(&data, |_k, (), ()| Option::<()>::None)
                         .probe_with(&mut probe);
                 }
diff --git a/src/trace/implementations/merge_batcher_flat.rs b/src/trace/implementations/merge_batcher_flat.rs
index d6296a4d8..ae8d2894f 100644
--- a/src/trace/implementations/merge_batcher_flat.rs
+++ b/src/trace/implementations/merge_batcher_flat.rs
@@ -7,23 +7,25 @@ use timely::{Container, Data, PartialOrder};
 use timely::container::flatcontainer::{Push, FlatStack, Region, ReserveItems};
 use timely::container::flatcontainer::impls::tuple::{TupleABCRegion, TupleABRegion};
 
-use crate::difference::Semigroup;
+use crate::difference::{IsZero, Semigroup};
 use crate::trace::implementations::merge_batcher::Merger;
 use crate::trace::Builder;
 use crate::trace::cursor::IntoOwned;
 
-/// A merger for flat stacks. `T` describes the
-pub struct FlatcontainerMerger<T, R, MC> {
-    _marker: PhantomData<(T, R, MC)>,
+/// A merger for flat stacks.
+///
+/// `MC` is a [`Region`] that implements [`MergerChunk`].
+pub struct FlatcontainerMerger<MC> {
+    _marker: PhantomData<MC>,
 }
 
-impl<T, R, MC> Default for FlatcontainerMerger<T, R, MC> {
+impl<MC> Default for FlatcontainerMerger<MC> {
     fn default() -> Self {
         Self { _marker: PhantomData, }
     }
 }
 
-impl<T, R, MC: Region> FlatcontainerMerger<T, R, MC> {
+impl<MC: Region> FlatcontainerMerger<MC> {
     const BUFFER_SIZE_BYTES: usize = 8 << 10;
     fn chunk_capacity(&self) -> usize {
         let size = ::std::mem::size_of::<MC::Index>();
@@ -61,8 +63,12 @@ pub trait MergerChunk: Region {
     type Val<'a>: Ord where Self: 'a;
     /// The time of the update
     type Time<'a>: Ord where Self: 'a;
+    /// The owned time type.
+    type TimeOwned;
     /// The diff of the update
     type Diff<'a> where Self: 'a;
+    /// The owned diff type.
+    type DiffOwned;
 
     /// Split a read item into its constituents. Must be cheap.
     fn into_parts<'a>(item: Self::ReadItem<'a>) -> (Self::Key<'a>, Self::Val<'a>, Self::Time<'a>, Self::Diff<'a>);
@@ -81,47 +87,48 @@ where
     type Key<'a> = K::ReadItem<'a> where Self: 'a;
     type Val<'a> = V::ReadItem<'a> where Self: 'a;
     type Time<'a> = T::ReadItem<'a> where Self: 'a;
+    type TimeOwned = T::Owned;
     type Diff<'a> = R::ReadItem<'a> where Self: 'a;
+    type DiffOwned = R::Owned;
 
     fn into_parts<'a>(((key, val), time, diff): Self::ReadItem<'a>) -> (Self::Key<'a>, Self::Val<'a>, Self::Time<'a>, Self::Diff<'a>) {
         (key, val, time, diff)
     }
 }
 
-impl<T, R, FR> Merger for FlatcontainerMerger<T, R, FR>
+impl<MC> Merger for FlatcontainerMerger<MC>
 where
-    for<'a> T: Ord + PartialOrder + PartialOrder<FR::Time<'a>> + Data,
-    for<'a> R: Default + Semigroup + Semigroup<FR::Diff<'a>> + Data,
-    for<'a> FR: MergerChunk + Clone + 'static
-        + ReserveItems<<FR as Region>::ReadItem<'a>>
-        + Push<<FR as Region>::ReadItem<'a>>
-        + Push<((FR::Key<'a>, FR::Val<'a>), FR::Time<'a>, &'a R)>
-        + Push<((FR::Key<'a>, FR::Val<'a>), FR::Time<'a>, FR::Diff<'a>)>,
-    for<'a> FR::Time<'a>: PartialOrder<T> + Copy + IntoOwned<'a, Owned=T>,
-    for<'a> FR::Diff<'a>: IntoOwned<'a, Owned=R>,
-    for<'a> FR::ReadItem<'a>: std::fmt::Debug,
+    for<'a> MC: MergerChunk + Clone + 'static
+        + ReserveItems<<MC as Region>::ReadItem<'a>>
+        + Push<<MC as Region>::ReadItem<'a>>
+        + Push<((MC::Key<'a>, MC::Val<'a>), MC::Time<'a>, &'a MC::DiffOwned)>
+        + Push<((MC::Key<'a>, MC::Val<'a>), MC::Time<'a>, MC::Diff<'a>)>,
+    for<'a> MC::Time<'a>: PartialOrder<MC::TimeOwned> + Copy + IntoOwned<'a, Owned=MC::TimeOwned>,
+    for<'a> MC::Diff<'a>: IntoOwned<'a, Owned = MC::DiffOwned>,
+    for<'a> MC::TimeOwned: Ord + PartialOrder + PartialOrder<MC::Time<'a>> + Data,
+    for<'a> MC::DiffOwned: Default + Semigroup + Semigroup<MC::Diff<'a>> + Data,
 {
-    type Time = T;
-    type Chunk = FlatStack<FR>;
-    type Output = FlatStack<FR>;
+    type Time = MC::TimeOwned;
+    type Chunk = FlatStack<MC>;
+    type Output = FlatStack<MC>;
 
     fn merge(&mut self, list1: Vec<Self::Chunk>, list2: Vec<Self::Chunk>, output: &mut Vec<Self::Chunk>, stash: &mut Vec<Self::Chunk>) {
         let mut list1 = list1.into_iter();
         let mut list2 = list2.into_iter();
 
-        let mut head1 = <FlatStackQueue<FR>>::from(list1.next().unwrap_or_default());
-        let mut head2 = <FlatStackQueue<FR>>::from(list2.next().unwrap_or_default());
+        let mut head1 = <FlatStackQueue<MC>>::from(list1.next().unwrap_or_default());
+        let mut head2 = <FlatStackQueue<MC>>::from(list2.next().unwrap_or_default());
 
         let mut result = self.empty(stash);
 
-        let mut diff = R::default();
+        let mut diff = MC::DiffOwned::default();
 
         // while we have valid data in each input, merge.
         while !head1.is_empty() && !head2.is_empty() {
             while (result.capacity() - result.len()) > 0 && !head1.is_empty() && !head2.is_empty() {
                 let cmp = {
-                    let (key1, val1, time1, _diff) = FR::into_parts(head1.peek());
-                    let (key2, val2, time2, _diff) = FR::into_parts(head2.peek());
+                    let (key1, val1, time1, _diff) = MC::into_parts(head1.peek());
+                    let (key2, val2, time2, _diff) = MC::into_parts(head2.peek());
                     ((key1, val1), time1).cmp(&((key2, val2), time2))
                 };
                 // TODO: The following less/greater branches could plausibly be a good moment for
@@ -135,8 +142,8 @@ where
                         result.copy(head2.pop());
                     }
                     Ordering::Equal => {
-                        let (key, val, time1, diff1) = FR::into_parts(head1.pop());
-                        let (_key, _val, _time2, diff2) = FR::into_parts(head2.pop());
+                        let (key, val, time1, diff1) = MC::into_parts(head1.pop());
+                        let (_key, _val, _time2, diff2) = MC::into_parts(head2.pop());
                         diff1.clone_onto(&mut diff);
                         diff.plus_equals(&diff2);
                         if !diff.is_zero() {
@@ -207,7 +214,7 @@ where
         let mut ready = self.empty(stash);
 
         for buffer in merged {
-            for (key, val, time, diff) in buffer.iter().map(FR::into_parts) {
+            for (key, val, time, diff) in buffer.iter().map(MC::into_parts) {
                 if upper.less_equal(&time) {
                     frontier.insert_with(&time, |time| (*time).into_owned());
                     if keep.len() == keep.capacity() && !keep.is_empty() {
@@ -247,7 +254,7 @@ where
         {
             let mut prev_keyval = None;
             for buffer in chain.iter() {
-                for (key, val, time, _diff) in buffer.iter().map(FR::into_parts) {
+                for (key, val, time, _diff) in buffer.iter().map(MC::into_parts) {
                     if !upper.less_equal(&time) {
                         if let Some((p_key, p_val)) = prev_keyval {
                             debug_assert!(p_key <= key);
diff --git a/src/trace/implementations/mod.rs b/src/trace/implementations/mod.rs
index e19712f06..e39522a7e 100644
--- a/src/trace/implementations/mod.rs
+++ b/src/trace/implementations/mod.rs
@@ -140,9 +140,9 @@ where
     type OffsetContainer = OffsetList;
 }
 
-/// A layout based on timely stacks
-pub struct FlatLayout<U: Update> {
-    phantom: std::marker::PhantomData<U>,
+/// A layout based on flat containers.
+pub struct FlatLayout<K, V, T, R> {
+    phantom: std::marker::PhantomData<(K, V, T, R)>,
 }
 
 /// A type with a preferred container.
@@ -400,49 +400,68 @@ where
 }
 
 mod flatcontainer {
-    use timely::container::flatcontainer::{Containerized, FlatStack, IntoOwned, Push, Region};
+    use timely::container::flatcontainer::{FlatStack, IntoOwned, Push, Region};
     use timely::container::flatcontainer::impls::tuple::{TupleABCRegion, TupleABRegion};
+    use timely::progress::Timestamp;
+
+    use crate::difference::Semigroup;
+    use crate::lattice::Lattice;
     use crate::trace::implementations::{BatchContainer, BuilderInput, FlatLayout, Layout, OffsetList, Update};
 
-    impl<U: Update> Layout for FlatLayout<U>
+    impl<K, V, T, R> Update for FlatLayout<K, V, T, R>
     where
-        U::Key: Containerized,
-        for<'a> <U::Key as Containerized>::Region: Push<U::Key> + Push<<<U::Key as Containerized>::Region as Region>::ReadItem<'a>>,
-        for<'a> <<U::Key as Containerized>::Region as Region>::ReadItem<'a>: Copy + Ord,
-        U::Val: Containerized,
-        for<'a> <U::Val as Containerized>::Region: Push<U::Val> + Push<<<U::Val as Containerized>::Region as Region>::ReadItem<'a>>,
-        for<'a> <<U::Val as Containerized>::Region as Region>::ReadItem<'a>: Copy + Ord,
-        U::Time: Containerized,
-        <U::Time as Containerized>::Region: Region<Owned=U::Time>,
-        for<'a> <U::Time as Containerized>::Region: Push<U::Time> + Push<<<U::Time as Containerized>::Region as Region>::ReadItem<'a>>,
-        for<'a> <<U::Time as Containerized>::Region as Region>::ReadItem<'a>: Copy + Ord,
-        U::Diff: Containerized,
-        <U::Diff as Containerized>::Region: Region<Owned=U::Diff>,
-        for<'a> <U::Diff as Containerized>::Region: Push<U::Diff> + Push<<<U::Diff as Containerized>::Region as Region>::ReadItem<'a>>,
-        for<'a> <<U::Diff as Containerized>::Region as Region>::ReadItem<'a>: Copy + Ord,
+        K: Region,
+        V: Region,
+        T: Region,
+        R: Region,
+        K::Owned: Ord + Clone + 'static,
+        V::Owned: Ord + Clone + 'static,
+        T::Owned: Ord + Clone + Lattice + Timestamp + 'static,
+        R::Owned: Ord + Semigroup + 'static,
     {
-        type Target = U;
-        type KeyContainer = FlatStack<<U::Key as Containerized>::Region>;
-        type ValContainer = FlatStack<<U::Val as Containerized>::Region>;
-        type TimeContainer = FlatStack<<U::Time as Containerized>::Region>;
-        type DiffContainer = FlatStack<<U::Diff as Containerized>::Region>;
+        type Key = K::Owned;
+        type Val = V::Owned;
+        type Time = T::Owned;
+        type Diff = R::Owned;
+    }
+
+    impl<K, V, T, R> Layout for FlatLayout<K, V, T, R>
+    where
+        K: Region + Push<<K as Region>::Owned> + for<'a> Push<<K as Region>::ReadItem<'a>> + 'static,
+        V: Region + Push<<V as Region>::Owned> + for<'a> Push<<V as Region>::ReadItem<'a>> + 'static,
+        T: Region + Push<<T as Region>::Owned> + for<'a> Push<<T as Region>::ReadItem<'a>> + 'static,
+        R: Region + Push<<R as Region>::Owned> + for<'a> Push<<R as Region>::ReadItem<'a>> + 'static,
+        K::Owned: Ord + Clone + 'static,
+        V::Owned: Ord + Clone + 'static,
+        T::Owned: Ord + Clone + Lattice + Timestamp + 'static,
+        R::Owned: Ord + Semigroup + 'static,
+        for<'a> K::ReadItem<'a>: Copy + Ord,
+        for<'a> V::ReadItem<'a>: Copy + Ord,
+        for<'a> T::ReadItem<'a>: Copy + Ord,
+        for<'a> R::ReadItem<'a>: Copy + Ord,
+    {
+        type Target = Self;
+        type KeyContainer = FlatStack<K>;
+        type ValContainer = FlatStack<V>;
+        type TimeContainer = FlatStack<T>;
+        type DiffContainer = FlatStack<R>;
         type OffsetContainer = OffsetList;
     }
 
     impl<K,KBC,V,VBC,T,R> BuilderInput<KBC, VBC> for FlatStack<TupleABCRegion<TupleABRegion<K,V>,T,R>>
     where
         K: Region + Clone + 'static,
+        V: Region + Clone + 'static,
+        T: Region + Clone + 'static,
+        R: Region + Clone + 'static,
         for<'a> K::ReadItem<'a>: Copy + Ord,
-        KBC: BatchContainer,
-        for<'a> KBC::ReadItem<'a>: PartialEq<K::ReadItem<'a>>,
-        for<'a> V: Region + Clone + 'static,
         for<'a> V::ReadItem<'a>: Copy + Ord,
-        VBC: BatchContainer,
-        for<'a> VBC::ReadItem<'a>: PartialEq<V::ReadItem<'a>>,
-        for<'a> T: Region + Clone + 'static,
         for<'a> T::ReadItem<'a>: Copy + Ord,
-        for<'a> R: Region + Clone + 'static,
         for<'a> R::ReadItem<'a>: Copy + Ord,
+        KBC: BatchContainer,
+        VBC: BatchContainer,
+        for<'a> KBC::ReadItem<'a>: PartialEq<K::ReadItem<'a>>,
+        for<'a> VBC::ReadItem<'a>: PartialEq<V::ReadItem<'a>>,
     {
         type Key<'a> = K::ReadItem<'a>;
         type Val<'a> = V::ReadItem<'a>;
diff --git a/src/trace/implementations/ord_neu.rs b/src/trace/implementations/ord_neu.rs
index 20b7cd002..f161bdc5b 100644
--- a/src/trace/implementations/ord_neu.rs
+++ b/src/trace/implementations/ord_neu.rs
@@ -11,12 +11,13 @@
 use std::rc::Rc;
 use timely::container::columnation::{TimelyStack};
 use timely::container::flatcontainer::{Containerized, FlatStack};
+use timely::container::flatcontainer::impls::tuple::{TupleABCRegion, TupleABRegion};
 use crate::trace::implementations::chunker::{ColumnationChunker, ContainerChunker, VecChunker};
 
 use crate::trace::implementations::spine_fueled::Spine;
 use crate::trace::implementations::merge_batcher::{MergeBatcher, VecMerger};
 use crate::trace::implementations::merge_batcher_col::ColumnationMerger;
-use crate::trace::implementations::merge_batcher_flat::FlatcontainerMerger;
+use crate::trace::implementations::merge_batcher_flat::{FlatcontainerMerger, MergerChunk};
 use crate::trace::rc_blanket_impls::RcBuilder;
 
 use super::{Update, Layout, Vector, TStack, Preferred, FlatLayout};
@@ -41,15 +42,17 @@ pub type ColValSpine<K, V, T, R> = Spine<
 >;
 
 /// A trace implementation backed by flatcontainer storage.
-pub type FlatValSpine<K, V, T, R, C> = Spine<
-    Rc<OrdValBatch<FlatLayout<((K,V),T,R)>>>,
-    MergeBatcher<
-        C,
-        ContainerChunker<FlatStack<<((K,V),T,R) as Containerized>::Region>>,
-        FlatcontainerMerger<T, R, <((K,V),T,R) as Containerized>::Region>,
-        T,
-    >,
-    RcBuilder<OrdValBuilder<FlatLayout<((K,V),T,R)>, FlatStack<<((K,V),T,R) as Containerized>::Region>>>,
+pub type FlatValSpine<L, R, C> = Spine<
+    Rc<OrdValBatch<L>>,
+    MergeBatcher<C, ContainerChunker<FlatStack<R>>, FlatcontainerMerger<R>, <R as MergerChunk>::TimeOwned>,
+    RcBuilder<OrdValBuilder<L, FlatStack<R>>>,
+>;
+
+/// A trace implementation backed by flatcontainer storage, using [`FlatLayout`] as the layout.
+pub type FlatValSpineDefault<K, V, T, R, C> = FlatValSpine<
+    FlatLayout<<K as Containerized>::Region, <V as Containerized>::Region, <T as Containerized>::Region, <R as Containerized>::Region>,
+    TupleABCRegion<TupleABRegion<<K as Containerized>::Region, <V as Containerized>::Region>, <T as Containerized>::Region, <R as Containerized>::Region>,
+    C,
 >;
 
 /// A trace implementation using a spine of ordered lists.
@@ -69,15 +72,17 @@ pub type ColKeySpine<K, T, R> = Spine<
 >;
 
 /// A trace implementation backed by flatcontainer storage.
-pub type FlatKeySpine<K, T, R, C> = Spine<
-    Rc<OrdKeyBatch<FlatLayout<((K,()),T,R)>>>,
-    MergeBatcher<
-        C,
-        ContainerChunker<FlatStack<<((K,()),T,R) as Containerized>::Region>>,
-        FlatcontainerMerger<T, R, <((K,()),T,R) as Containerized>::Region>,
-        T,
-    >,
-    RcBuilder<OrdKeyBuilder<FlatLayout<((K,()),T,R)>, FlatStack<<((K,()),T,R) as Containerized>::Region>>>,
+pub type FlatKeySpine<L, R, C> = Spine<
+    Rc<OrdKeyBatch<L>>,
+    MergeBatcher<C, ContainerChunker<FlatStack<R>>, FlatcontainerMerger<R>, <R as MergerChunk>::TimeOwned>,
+    RcBuilder<OrdKeyBuilder<L, FlatStack<R>>>,
+>;
+
+/// A trace implementation backed by flatcontainer storage, using [`FlatLayout`] as the layout.
+pub type FlatKeySpineDefault<K,T,R, C> = FlatKeySpine<
+    FlatLayout<<K as Containerized>::Region, <() as Containerized>::Region, <T as Containerized>::Region, <R as Containerized>::Region>,
+    TupleABCRegion<TupleABRegion<<K as Containerized>::Region, <() as Containerized>::Region>, <T as Containerized>::Region, <R as Containerized>::Region>,
+    C,
 >;
 
 /// A trace implementation backed by columnar storage.
diff --git a/tests/bfs.rs b/tests/bfs.rs
index 930f4fead..dee2a9e2c 100644
--- a/tests/bfs.rs
+++ b/tests/bfs.rs
@@ -17,7 +17,7 @@ use differential_dataflow::Collection;
 use differential_dataflow::operators::*;
 use differential_dataflow::lattice::Lattice;
 use differential_dataflow::operators::arrange::Arrange;
-use differential_dataflow::trace::implementations::ord_neu::{FlatKeySpine, FlatValSpine};
+use differential_dataflow::trace::implementations::ord_neu::{FlatKeySpineDefault, FlatValSpineDefault};
 
 type Node = usize;
 type Edge = (Node, Node);
@@ -246,8 +246,8 @@ fn bfs_differential_flat(
             let (edge_input, edges) = scope.new_collection();
 
             let c = bfs_flat(&edges, &roots).map(|(_, dist)| (dist, ()));
-            let arranged = c.arrange::<FlatKeySpine<usize, _, isize, Vec<((usize, ()), _, _)>>>();
-            type T2 = FlatValSpine<usize, isize, usize, isize, Vec<((usize, isize), usize, isize)>>;
+            let arranged = c.arrange::<FlatKeySpineDefault<usize, usize, isize, Vec<((usize, ()), _, _)>>>();
+            type T2 = FlatValSpineDefault<usize, isize, usize, isize, Vec<((usize, isize), usize, isize)>>;
             let reduced = arranged.reduce_abelian::<_, _, _, T2>("Count", |_k, s, t| {
                 t.push((s[0].1.clone(), isize::from(1i8)))
             });
@@ -315,7 +315,7 @@ where
         let edges = edges.enter(&inner.scope());
         let nodes = nodes.enter(&inner.scope());
 
-        type Spine<K, V, T, R = isize> = FlatValSpine<K, V, T, R, Vec<((K, V), T, R)>>;
+        type Spine<K, V, T, R = isize> = FlatValSpineDefault<K, V, T, R, Vec<((K, V), T, R)>>;
         let arranged1 = inner.arrange::<Spine<Node, Node, Product<G::Timestamp, _>>>();
         let arranged2 = edges.arrange::<Spine<Node, Node, Product<G::Timestamp, _>>>();
         arranged1