The Rustoleum clear is not the least bit fuel resistant, though the enamel colors are(but not the metallics). I use Clear Lustrekote on 2 week old Rustoleum, and dust it several times over a couple of hours before laying on the shiny glass coat. In a year or so it'll start to spiderweb crack, but it's as fuel proof as anything short of polyurethane or epoxy paint. Rustoleum goes on thick and heavy. I recommend using flat colors which go on lighter and adhere better(in my experience), and after the Lustrekote, they look just as glossy as the gloss colors would have. And the Lkote seems to bond better too.
However, I think Rusto has changed the formula and isn't as good as it was a few years ago. I've switched to Duplicolor acrylic lacquer, which is fast drying, in one day, and goes on thin and light with very little extra weight. Use NAPA DC540 primer/filler and you'll have the best paint job you ever saw from a rattlecan. The nozzles are superior too, with a triangular knife-edge spray pattern and an adjustable nozzle. Auto parts stores have the colors, and the primer had different part numbers but may be the same. DC540 is in a NAPA labeled ca. They also sell the Duplicolor lacquer colors. DC also comes in enamel. It's fuel resistant like Rusto was, quicker drying(one day), but much heavier than the lacquer. With the acrylic lacquer, you need to fuelproof it. Lustrekote plays well with it, but I'm using butyrate dope on everything but the nose, which gets Lustrekote.
Rusty