Bruce, I usually apply three color coats of paint on my bodies at 20 minute intervals. I then clear coat the body the same way 24 hours later. I've never had a problem doing this. As for the wrinkled spot on the roof, you didn't say whether you were using enamel or lacquer paints. If lacquer I would let the paint "cure" for a week, sand the wrinkles out, mask the body and re-shoot the roof. If enamel paints were used I'd let the paint "cure" for 'bout a month and then sand the wrinkles out, mask the body, and re-shoot the roof. I hope this helps.