How to keep fuel up to the curb after shut off.

I had an AFB on a car that would boil off just as the OP describes. The insulating carb base gaskets didn't do much for that. I ended up making a plate type insulator, ala the Z-28 DZ302 part, and that worked much, much better at slowing/stopping the boil off. It was nearly the same width and length as the intake itself. I painted the top light gray to go with the rest of the engine, and took the bottom to a nearly polished condition.