Actually most people airbrush at 30 - 35psi for nail, I prefer 30.
Nowadays would steer clear of a preset compressor. It may seem like a bargain now but think ahead, a regulator is a must. In the future you may want to use it for other applications such as tattoos 15 - 20 psi, tanning - 10psi or make-up and facial tanning 7 psi.
Best wishes
Pat