I use all different types of paint. It really depends on the color. Typically i use Formula U, Perfect Paint and Testors enamels. If you use enamel spray then be sure to clear coat it with a fuel proof paint. Your Polyurethanes are fuel proof up to 15-20%. I've been using Perfect Paint clears lately because they dont yellow as much as the Polyu's. Prior to clear coating you can add decals and trim tape. Then seal everything.
A word to the wise. Allow a minimum of 48 hrs between colors if you are masking. Also use a low tack mask. Car painters have an excellent low tack tape or just use electrician's tape. Its pliable. I'll try to send you a pic of my last project.