Install on top of existing OpenBSD?

[flushTLB]

First, thank you so much for creating and maintaining UTMFW - I'm looking to create an OpenBSD-based transparent firewall with a good GUI and this looks like the perfect solution.

I was wondering if you would be able to provide a reduced set of installation instructions (or, ideally, an installer script :)) for those of us who just want to install UTMFW on top of an existing OpenBSD system, rather than having to fully format and do a clean install of the ISO. It looks like the build instructions were intended for creating full ISOs. Thank you!