How good are your high pressure plumbing skills?
The unit I use is a scuba paintball fill yoke and a specially made Palmer Stabilizer that regulates from 3000 PSI to 900 Max PSI. I use this set up for gun testing to tire filling and changing.
A more cost effective solution would be to connect a compressed air tank to a SCUBA fill yoke with a piece of steel braided hose.
Tank with fill yoke--->steel braid hose (3' long)----> 3000/48 steel tank ----> coiled remotes rigged to come off the 3000/48 tank with the use of high pressure rated hydraulic fittings.
The coupler on the fill yoke would be removed as well as the fill nipple. Use an appropriate thread sealant. Loctite makes a thread sealant rated up to 6000 PSI. I found it at a truck supply store. The hose would allow alternate secured mounting locations within the shooting gallery. If you cannot find the steel braided, you can use hydraulic hose rated for 3000 PSI. A local hydraulic shop may have the 1/8 inch NPT fittings to crimp onto the correct hose. The other issue hydraulic hose does not coil up as tight as a thinner steel braid since the bending radius is different. While at the shop you can inquire about high pressure steel fittings to make dual remotes. You will need an 1/8 inch NPT Female T with a Male bull or Female X Male X Female.
C/A adapter ---> T fitting ---> remote hoses with slide checks or quick D couplers with ASA adapters.
When it comes time to airing the air system up, make sure the bleeder valve on the filler yoke is closed. Turn the tank on slowly until fully pressurized. Make sure all fittings are tested for leaks. Secure the bottles to a sturdy place like a thick post with straps. When I set up the make shift fill station at the team's makeshift location, I strap the tanks a fence post we have in the staging area.
I have seen this rig in many paintball tanks for the defense armament. Good luck I hope this helps.