Brian 15 coats? paint become brittle with more than 3 mills on there. I have used PPG, DuPont, PCL, and others -- base coat, thin clear coat, dry then color sand, add decals and custom stripes, two top coats possible three of clear. You do paint far better than I do so I am not trying to debate this. I have put intricate flames on old cars with less steps. I wish I had the time and you felt like walking me through your work area sometime I might learn something. Sam DiBartolomeo in Southern CA