Spent about as much time researching as painting for this step.
I wanted to get the inside painted so I can start bolting thing into place.
I ended up using Krylon Fusion rattle cans. Twilight Grey satin. The stuff is supposed to bond to anything! I wiped the existing wash prime that was applied during the quick build with a damp paper towel with MEK on it to clean and soften it a bit but not remove it. This has worked well for otheres and I expect it will for me as well.
The satin finish is to try to keep some light from reflecting up onto the cockpit bubble.