I used the approach you have described, but spend a few dollars on three or four rolls of easy peel masking tape to keep the Black of the face surface of your parts outside the joint or it will be a real pain come time to do your painting prep. It takes a bit longer to prime, assemble the joint, mask, dissemble, Black, dry, unmask, assemble, then rivet each exterior joint but I would do the same again. Once the Black dries it is very hard to shift with GP thinners or Prepsol, both of which mess up your base coat of primer.