Well Andrew.....I'm really not one that should be telliing others how to airbrush but I'll tell you how I do it. I do have the Paasche H airbrush. I use either Ceramcoat or Anita's arcylic paint from HL. I always thin the paint 50/50 with Windex and make sure the paint is mixed really well. I set my air pressure at 25psi with a working pressure of 20psi. I played with air pressure off and on for a few months and the 20-25psi seems to work best for me. I did a ton of spoon test and for me it was ok for checking color and shin but as far as painting a larger body you'll just have to experiment. For me, and I can't stress this enough you need to airbrush when there is low humidity. Here in southern Indiana it needs to be below 70% for it to be an exceptable paint job for me. I hope this helps.