Find what detail spray gun you would like to use, and see what it's CFM requirements are. Then, double that, and look for a compressor rated for that. (if the mini-hvlp uses 4 cfm, get a compressor rated for at least 8 cfm. Or, at a minimum, 6 cfm).
The Asturo 878WB mini-gun is rated at 3 cfm, which is the lowest I remember seeing anywhere. I also like mine so much I passed on a SATA Minijet and bought a second one. The 1.2 tip works great for clear (the 1.0 works well, too, but works best if you over-reduce VERY slightly).
Asturo Low Air Spray Gun
As far as compressors, I've had a 2hp, 5 gallon Harbor Freight twin tank that lasted me several years of airbrush and mini-gun duty, and is still kicking running nail guns for my brothers construction company. And, I've seen plenty of people who dropped a lot of extra money for a name brand only to have a ton of problems.
My general rules for buying compressors are
-get one bigger than what you think you'll ever need. At worst, you under-use the compressors capacity and extend the life of the compressor.
-stay far, far away from "oilless" compressors. They're loud as hell, run hot, pump a bunch of moisture into your lines, are inefficient, and don't last long with regular use.
-Buy American if possible. They tend to come with better warranties. With a cheaper, Chinese compressor, you might get one like my HF compressor that is indestructable, or you might get a POS out of the box.
Like most things in life, the more you can spend up front, the less likely you are to have issues later on.