I also own an Iwata Smart Jet air compressor, but if I had to do it over again I would probably buy a compressor with an air tank and a true regulator like this one.
https://www.amazon.com/Master-Airbrush-Model-TC-40T-Single-Piston/dp/B00WBT7PTW/ref=sr_1_2?ie=UTF8&qid=1518468660&sr=8-2&keywords=badger+air+compressor&refinements=p_72%3A2661618011