Ive got the parts in question off the car and in the garage in a work bench, side mouldings, and rear boot strip.

Ive painted with a compressor before and that came up mint, so im guessing its just the cans thats causing the problem, i did that with the headlights, did a dust coat, let that dry then a complete covering so they were soaked and came out ok, i just dont want to go so far that i get runs and end up having to spend more time flatting the runs out and re doing it