[72HuggerK20]

First of all, your sanding technique sounds like it needs work. You will want to sand any surface you are going to prime at least up to 150, prime it, and then sand the primer with 220, 320, 400, and 600. Any sand-through spots should be touched up with some etch primer (spray can is fine) before painting. Also, to use less paint, get the proper shade sealer and spray a coat of that first. It will give you an even tone to lay your color on, and it'll take less to get even coverage.

As for the gun settings, I'd have to play with the gun to make sure it doesn't act weird, but usually I run the fan wide open, the fluid wide open to where the trigger won't move any farther back and then back in a quarter turn. Also I run the the air adjusting knob wide open. There is no need to use the air adjustment knob when you are using a regulator. It's just redundant at that point. The only things I adjust are my air pressure (with a regulator at the inlet), my distance from the panel, my speed, my overlap, and sometimes the fluid with my trigger finger when doing a blend. My guess is that you'd want to run that gun around 25-29 psi, and drop it a little like you are to do your drop coat. Usually 50% overlap and 4-7 inches from the panel, but the drop coat should be 80-90% overlap and about 10-12 inches from the panel.

To avoid "tiger striping" you may want to switch up the directions you apply each coat. So if your first coat is applied by moving side to side, the next one go up and down.