Unless its a heat cured auto enamel, it wont be fuel proof. I used some automotive clear coat thinking it would be fuel proof, and it got all tacky and gooey after a few flights. Rustoleum is good, but goes on heavy. Also the white will turn yellow after a while.
I haven't tried catalyzed clear, where you mix 2 parts and reducer to see if it is fuel proof. It might be, but its also expensive.