Thanks PJ! I figured out the problem with the 6" buffer, so I've been polishing stuff while waiting for paint.
I'm thinking of putting on 2 coats of clear on the hubs, then put the black pin stripes, then one more clear.
As far as the rim that was primered before painting, it turned out poorly. I'll re-evaluate it before I put down a second coat, but chances are I'll be sanding it down and repainting. Too much texture left behind by the primer.