the big advantage of rattlecan enamel versus automotive paint is safety. Unless someone is willing to invest in equipment, rattlecan is much safer. I have wondered if my asthma is related to my use of isocyanates under less than perfect conditions. I was probably one of the first people to use urethane clear in the bike industry, the autoparts guy recommended it. Said the local NASCAR team used it over lacquer. That was back when catalyzed acrylic enamel was meant to be a topcoat. You can still get paints like that for a single topcoat application, I have considered it.