I made some stands for the parts. Holding parts firmly so the whole thing can be sprayed is one key part to successful paint job.
First time I tried to spray primer I made every mistake in the book and did no priming. I had to get a large tip for my gun. Here are some things I learned.
Primer requires 1.6 - 1.9 tip. Paint uses a 1.3 tip. Gun drops pressure 15 psi. So to get a cap pressure of 10 psi you need an inlet pressure at the handle of 25psi. Spray within 8 inches of material. Beyond this and paint lands too dry. But too close and it runs. Flaws can be sanded out and buffed. Buffing works.
I primed the wheel pants. Turned out there were lots of wrinkles, flaws and other bumps I wanted to sand out. So I sanded with wet P400 sand paper. I did about 3 or 4 iterations of prime sand - prime sand until they looked fairly smooth. Then I painted them.