How big a compressor you need depends on the gun/tip you are using. They will tell you how much air you need. And whatever type of paint you use will also tell you what pressure/volume/temperature to paint at. TEMPERATURE is a critical value. Too cold, the paint will run. Too hot the paint will dry before it flows out.
And you will need a water separator. Nothing more frustrating than a drop of water in the middle of the hood.
Watch several youtube videos to learn the technique. Several because a few will be absolute crap. But after a few you should pick up the key points.
Read all the instructions and do as they say.
Re the white vs blue metallic thing. Honestly white is one of the hardest colours to apply correctly. Quite right blemishes might be hard to see but so is watching your progress/technique. Darker colours are way easier to see how the paint is going on. Solid White or Metallic Blue, they both need the same attention to detail/technique. And they both look like shit if you are too lazy to be methodical. It is not rocket science but everytime you refill the cup you need to follow every step of the process. I painted in my Dads garage, he loved to be there and he was my checklist.... He timed how long we mixed/stirred the paint, went thru the checklist every time, kept me on track. It was great fun. He was a car guy too. Miss him lots.
My old paint gun, a Sharpe 75, needed 11cfm at 50psi. I've still got it but have not painted a car in 40 years. I do plan to paint my TJR in 6 years, when it turns 20 and I turn 70.