1200 would be OK to knock off the really bad spots, but I would finish with as high a grit as you can find, maybe 4000. You didnt say what brand of enamel, but make sure it has cured thoroughly. If it still smells, its not cured. I airbrush enamel at between 20-25 lbs, thinned 1 part paint to 2 parts lacquer thinner. Good luck!