I have several scuba tanks from 60 cu.ft. to 100 cu.ft 3420 psi,alot of refills for my talon .25,and for my Maurader ,thats alot of none stop shooting and then for hunting i have a 47cu.in. and 13cu.in,in the maurada the 47 is good for about 6 refills in the field and the little 13 is good for about 4 and thats more than enough for squirrel hunting
Alot of dive shops will fill your tanks ,some require a waiver stating that it is for airgun only. The more you go there the better they know you,i have one shop ,owner is a PCP shooter.
And the JDS regulators can be ordered in 2,000 and 2500 psi.