I have been using Rustoleum for years and yes it is fuel proof to a point. I hit it with some 35% fuel and it came off in sheets. But with 15% and below it works great, and that's with all the solid colors I have used. That includes green, red, light/dark blue, yellow, white and orange. I agree it is best to give it a week to cure, I didn't do that with yellow and I did loose a little but it too eventually became fuel proof. Regarding the clear and matalics I have no idea, never used them. One last thing I recently tried Lustercote over Rustoleum and it work fine, there didn't seem to be any interaction problems with Lustercote over Rustoleum.
Andy