When you set the pressure or talk about pressure does it mean that's the target pressure? Because for e.g. if I'm to get pressure of 30psi at the tip, that means I need to set it a bit above 30psi on the compressor as when I press the the trigger on the airbrush the needle goes down.
Adjust on the fly. So depress on your airbrush and adjust regulator to desired setting. When you release the regulator will rise slightly again but you are now good to go at your set pressure. Just noting 30PSI is very high for most paints.
I usually spray at 30-35 psi. I want the paint to be a fine aerosol before it hits the target surface.
Just saying!
I agree with Warren, you can adjust the pressure at the regulator it with the airbrush in use. I've never found it necessary to make fine adjustments to the pressure, but if you feel it will help, then it would be worth investing in a MAC valve, which can be fitted between the supply and brush and will allow fine adjustment.