Gail,
Not really sure what you are asking but...
If you have a 20lb co2 tank for inside get a welding regulator for it and have the bottle connection on the regulator, changed for the Co2 tank. welding shop can do that. (has to be a oxygen regulator for gas welding or a breathing O2 regulator will work but have to change the stem/tank connecting tube on the regulator.).
Maybe even your regulator can be adapted by a welding shop that sells and refills tanks.?? They have all types of adaptors.
As far as the air line steve has the little plastic quick connects (like came with the airgraver) just put one in the line from the tank and you should be able to move the airgraver to ether location without messing with regulators.
the welding regulator is screwed on to the tank by the stem so you don't have to mount it anywhere..
Hope this helps.
AirAmp