I went the hand pump route on the first rifle. It can definitely wear you down. Carbon fiber tanks are expensive but a one time cost. Scuba tanks are generally not recommended. Getting a fill at the scuba shop is not to expensive but buying your own compressor is quite expensive. Check how much pressure your scuba shop can fill to. Some PCP air rifles can go to a very high pressure but the scuba shops often don't have the the equipment to charge them to their full potential.
Or you can just buy a nice springer which is plenty for rabbits at 50 yards.
Or you can just buy a nice springer which is plenty for rabbits at 50 yards.