Support of Float and transparency

[lhils]

Hey,

started a few weeks ago to use the software and I'm generally impressed by the stuff that you can do and use. A job well done!

However to some clients we would like to visualize a few things so they understand it better. Maybe I haven't found every option or I'm using something wrong but the option to delay and earliest begin isn't a hundred percent what I'm looking for.

From experience a certain Task needs a specific amount of time, however there can always be some unforeseen events, e.g. shortages, illness, etc.
Our idea is to show the clients that a project should use float to have a better experience for all. So if the project is planned perfectly it takes X amount of time but we can or want to promise it can be done in Z amount of time. If the project is completed in X amount of time everybody is happy and if it happens to take Z amount of time it's been planned for and there's no arguing about it.

I hope the added picture shows what I was trying to explain:

To show the float I personally think the same color of the Task with something like 50% transparency would do the job.
And if there's a possibility to have a grouped task shown as in the picture it would be awesome. Thanks in advance.