[Mr V]

I think you are likely going to run into problems powering the compressor with that power supply. The compressor can draw ~20amps on start up and ~10amps when running.

I'm also not seeing any sort of relay to control the compressor. The FIRST legal pressure switch can't handle that many amps. You can use a common automotive relay to control it. wire the pressure sw inline with the relay's coil and you'll be good to go. Look for a universal relay often sold for driving/fog lights, they are typically rated for at least 20a and many are rated for 30a or 40a.