I run a power tank.
I also bought an inline constant 80 psi. regulator from mcmaster carr, and put that in right before the arb selenoid.... That way i could accidently bump my power tank regulator up to 120 psi and the constant regulator will always kick it down to 80 psi preventing me from blowing my arb seals. /forums/images/graemlins/thumb.gif
The only problem with a small tank, it depends on how many times your going to be locking and unlocking your arb.. if you were on a whole weekend trip, i'd say you'd want a powertank then.. It should only be releasing air when you turn off the arb and it goes PSSHHHT.. otherwise it's not consuming any air, just using the 80 psi to hold it locked. /forums/images/graemlins/pimp1.gif