Armor Coat rust enamel (also sold by Canadian Tire) is what I use on all rowboat motors that I do paint work on.
When it cures, it is a "fuel resistant" as anything I've ever used. If you spill or drip on it, and completely wipe it off within a few seconds, there is no damage to the painted surface.
Like most paints, leaving the fuel on there for an extended period of time will end up in streaking (or worse), even if they seem "resistant" to fuel. None of them are bulletproof when it comes to prolonged or long-term exposure, and overnight exposure would qualify as such.
I've used his aerosol paint in my restorations and never had a big fuel leak or spill but have certainly gotten some fuel drops on the painted finish around the fuel connection. Also had a carb flood one time that spilled some gas on the paint and nothing happened. In one section of his site, Peter does use the term "gas-proof" with regard to the aerosol paint (see link below). Sorry you had that happen. I still think his aerosol paint is great stuff and will continue to use it until I get some spray equipment. Guess it would be best to use a urethane paint on the fuel tanks.
I'll continue to use it as well. I have 2 other tanks that were painted about 10 years ago and they are like new.
The problem was the gasket that leaked. It got hot and the gas must have expanded. Nevertheless, the gasket shouldnever have leaked. It was brand new. Was it old stock that was dried out? Did I not tighten the bolts enough? I dunno.
Next time I'll add a sealer on both sides of the gasket when I tighten it down. Any suggestions on what material to use? It may contact the paint for sure...