Apply resin then hover over with heat gun until they all pop.

how to avoid pin holes?

I use a 3 to 1 Epoxy from Composite Envisions.com

and the layers vary until i have a uniformed flat surface. All of these parts I did as Overlay on the original parts, not Vacuum Form, or Infusion. They are original parts wrapped in carbon fiber and resin up, sanded down and resin up over until i am satisfied. Many tell me that they actually look like vacuumed carbon pieces.

what epoxy resin you use?how many layers?

sand and clear coat using Automtive clear coat. Then sand that down and buff polish.  I use Epoxy resin on the parts.

How you finished on parts? sanding polishing resin? epoxy or polyster?