Ive got the walnut one and de-shrouded it, (didn't like the tac stock on this gun) the reg is still the unreliable same, not sure about the fill up off the gun, but i think you can do it with the right fittings. I had mine regged and tuned by JB and its now very accurate, with about 130 good shots. It might make sense picking up a 2nd hand one thats already had everything sorted out on it for around £600? good luck
BSA R10 se .177 walnut, bowkett blueprint & reg'd, optisan 6-24x50 ffp - BSA T10 scorp .22 tac, xtx huma reg'd & tuned, hwk tac 30 8.5-25x42 - A&M mods