OK I see what your talking about, man that is not going to be easy to mask and paint. if you are just doing the black what about pin striping tape in different widths works pretty good on side trim moldings.
I just watched the Eastwood powder coat video, they do show some hi-temp masking tape. Your suggestion of pin striping tape is a good one instead of a coating, I could see that working on the black surround line.
