I have a single and a couple of double action Paasche air brushes. The doubles were my fathers and I can't keep them from splattering and cant spray a small dot. I've always used the single. With the same paint and pressure in the single, no problems. I've taken the doubles apart and think I know how to use them in removing the handle and sliding the needle and button back full pressure and forward reduced. Don't see the advantage of the double except can one hand it. Is the problem with the needles in the doubles? Also, is Paasche the airbrush of choice?