Or an inexpensive airbrush with aerosol can/small compressor. Basically the same as the Preval but with more control. I have a better one that I've used to paint some cams (and other things obviously) but you don't need anything great for that. Handy things to have around for paint touch-ups.
Ditto above about thinning, settings, and prep. Also, much better to go with more very light coats. However close you think that you should be when spraying, back it up a little and do less at one time. Dust, let it dry at least to flashing off. Then another very light coat. You'll get a better finish that way and no runs/drips which will be irresistible to try to fix and then you'll just F' things up worse when you try. ; )