I have a couple of questions on shooting the clear over the color on plastic parts:
1. Do you have to do scuff up and clean the color again to remove contaminants prior to clear coating?
2. If it's been a few days since doing the color, what prep work do you recommend prior to shooting clear? - probably same as #1 question.
3. Do you just put 1 light coat of clear?
Apply the Adhesion Promoter per the instructions on the can. I believe you spray one light coat and wait 5 minutes. Then one med/wet coat and wait 15-20 minutes. Then you can start spraying light coats of color.
If you spray light coats, you don't have to wait very long between coats. Spray 1 or 2 light coats of clear after you have 2-3 light coats of color on the piece. You don't let the color completely dry before spraying the clear.
I like Landau Black for plastic interior parts. I use Trim Black for metal parts and plastic parts that aren't in the interior.