Having worked in a body shop for 14 years and been around them all my life,my advise is buy the biggest you can afford,regardless of what you plan do to with it.....
Dual stage,220v with the biggest tank you can find is the best.....One shop I go to has one large compressor on a tank I'd guess to be about 100 gallons and then another tank I'd guess to be at least 250 gallons,he runs a rather large shop on this one compressor...You not only need pressure,but you need volume.....Stay away from the oiless ones,they generally do not last...
The shop I worked in had one Gilbarco dual stage with a 7.5 hp motor and 80 gallon tank. We were 6 employees and that compressor is still running today and was bought new in 1974......We would change the
oil and air filter once a year whether it needed it or not and that is all the matinence we did on it...The compressor has worn out at least 6 or 7 electric motors to date,runs five days a week,50 weeks a year....
When you pipe your shop,I'd also recommend 1.5in diameter hard lines and put a water trap on every line....
One day went I went to pick up a new electric motor for the shop compressor,I noticed an air compressor apart in a box sitting on an 80 gallon tank covered with dust and junk,been sitting there for 5 years. Owner bought it and decided to overhaul it first and never got around to doing it once he took it apart. I bought the whole thing for 150 bucks with no motor.. 55 bucks for rings and gaskets and another 150 for a heavy duty 5hp electric motor,been running for 15 years now at my house and it will outlive me!!!!!!!! It is a dual stage American Kellogg and will run any and everything I can hook to it...Piped my shop with 1.5in pipe and I have four outlets around the shop with water traps on each one...No regrets at all.....I have been offered a thousand bucks for it several times,someday when I'm gone my daughter or wife will probably sell it for 100 bucks just to get rid of it though....
Check with your local body and mechanic shops in the area as they sometimes have spares or when one brakes they do ot have time to repair it,so they just buy a new one,they can not afford the down time....Good deals are out there..
Over the years,I have picked of five for little or nothing,cleaned them up,painted them and resold them for a very good profit....Everything from the little Sears type portables to shop compressors the size of mine,never had one for sale more than a few days before I got my asking price....
David