I really like the selection and ease of Krylon and Rustoleum in the rattle cans too, unfortunatly I've run into the same problems as you as well.
Bad news,
After reading dozens and dozens of posts on paint over the past several years it is my understanding(and further experience) that there aren't any off the shelf, readily available, paints that will stand up to nitro. There were several people who said that they had good results with various rattle can colors and clears, including krylon, varathane, polycrylic spray, rustoleum and dupli-color...My personal experience, after reading these post and doing test panels, is that none of them hold up to raw or hot fuel.
The only 1 part, ready to spray, product off the shelf that has been any good is lusterkote clear, (except that over krylon O.D. green it wicked up the color over 2 years and turned black in several spots making the rear top fuselage on a desert camo ME109 turn all one color...black[
]). Any relative humidity over 60% makes it milky to varying degrees as well, especially the flat. For me, several light mist coats and later, a heavier coat, has worked well over all of the Home Depot, Lowe's and auto parts store paints with out crazing or orange peeling. Others have had disasterous results over enamel.
Good news,
Some auto paint stores will mix either or both catalyzed(2part) enamels or catalyzed laquers in clear or color and put them in a rattle type spray can for you. This route has a very limited shelf life, as in 24-48 hrs max, once mixed in the can. If you are able to spray your own, you can get the paint and the catalyst seperately and mix/spray your own. This has also worked well for me in the past (both ways).
By far, I am really happiest with both the Nelson's Hobby catalyzed clears and the KlassKote clear 2 part spray epoxy. Both are pretty easy to work with if you have any spraygun experience at all. The nelson's does fairly well when brushed on as well, and is water clean-up . Haven't tried the KlassKote brushed yet, but it does spray nicely. Higher humidity hasn't been an issue when spraying yet for either one, which is good for me. We don't get a lot of warm, low humidity days in NC.
http://www.klasskote.com/
http://www.nelsonhobby.com/paint.html
good luck!