For practicing in the backyard hand pumping could become a pain, but unless your hunting nuisance birds, I don't think you're really going to need to refill mid-hunt. Do you use more than 20 rds hunting with a 22lr? If not, then you still have a cushion of 5-?????.
How many shots per fill with be determined on how you set up the power usage. Use all your knowledge of P/Bers. The twist is constant. You have pellet weight & fps that are adjustable. So if you shoot a lighter pellet you will probably not to reduce the air used with each shot or the fps will increase so much that the twist will destabilize the pellet. A heavy pellet with low air and you may not have enough twist to stabilize and accuracy suffers.
This is the beauty of being able to adjust air pressure per shot. With a springer you have to find the pellet it likes. With the adj pcps (even the discovery can be modded) if you need a higher shot count, adjust the air per shot down & test diff pellets for accuracy. Naturally, since the twist fixed and each pellet has a max & min velocity that it performs best, you'll probably find a lighter pellet is more accurate.
So limit the size of the game or the max distance you shoot. Now if distance is limited, you may still use a heavy pellet. For instance at 25 the heavy pellet is just as accurate as the lighter at 100. Know the outside limits with each set-up.
Personally I like accuracy over extra power most of the time. A lot of posters have their marauders set up for max power & shoot the heaviest pellet possible at optimum speed for accuracy & only get only a few shots. If your only shooting rats in the barn this would be a horrible setup for. Great for larger game.
If you go for max power & a higher refill rate then you're likely to hate the pump. Most posters consider the pump to be only marginally usefull with 3000 psi tubes. If the money is do-able and a refill station nearby then the 4500 psi carbon fiber tank is definitely the easiest to transport. Scuba tanks are cheaper... don't know the cost of the valves, but it may be less than the $300+ you'll spend on a good hand pump. I've got the "cheaper" Benjamin pump for the discovery & when it's dialed in I probably won't hate it sooo much. Checking accuracy & shot count on mulp pellets.....make a tweak & start over.....hours turn to days. More pumping than shooting and that's on a disco. 3000psi Marauder, I'd rather poke my eye with a stick
Perhaps it's easier with the really expensive hand pumps.
