Hey, Brian -
Just a sample of what works for me:
Tamiya acrylic, usually no less than 50% X-20A, sometimes up to 70%, medium tip for the airbrush, PSI 14-17.
Model Master enamel 30-50% enamel thinner, PSI 15-20.
Testors small jar gloss enamel, 25-30% enamel thinner, 15-20psi.
I use Iwata fine tip single action, Paasche VJR very fine tip. Badger is brand most used, 200G single action, 100G dual action, 100LG, 105, 105 Extreme and Sotar 20/20. I have a variety of needle/nozzle sets for all of the Badgers, to accomodate jobs to be performed.
I rarely use lacquer thinner to reduce anything, but will if I'm concerned about "bite" for better paint adhesion.
Model Air provided a very nice finish, but for whatever reason I just never got it to work for me.