Not that this will effect many here however I thought I would pass along my exp.
Recently I was setting up a CO2 (20lbs) tank rig for the airbrush I had an old Regulator & tank setup and needed some help coverting it to work with CO2 and changing to output fitting for the 1/4 airbrush line fitting.
Anyway long story short the folks over at General Air Service & Supply
http://generalair.com/ (in Denver, CO) took care of me and were very cool I would recommend them to any in the area looking for a CO2 setup.