right ive had a look and it does look possible, butit would be a case of trial and error.
i put about 5 shims in mine to get around 900psi but i started at about 600psi and obviously it vary fromreg to reg.
what u need to do is ad 1 shim at a time and see the results obviously this wastes a lot of air as u have to dump the bottle every time, so i would only fill to aboutt 12-1500 psi at a time a dive bottle would be handy unlessu have a compresser to hand, also a spare 1.5k burst disk just incase u go that little bit too far as a little make a lot on a reg