Serems the gamo is covered.
Dont get too hung up on " 2 stage, 3 stage, ...., blah" these days ( and since they came out) all pre-charged hand pumps are pretty much the same esp. from just a pumping point of view.
I have had the yellow hill, black "AF" FX gen 2, currently a $100 Chinese ( and a 4,500 scottpac) the first one cira: 2000 was SLIGHTLY more difficult to use, all others mostly the same.
At 135lb's NO issue using a hand pump even on first fill on a 490cc tank and certainly not with just top off's. I know a Feild Target shooter who intentionally pumps during the shoot trying to increase his heart rate.
Pumping is 99% style,, lift handle, push handle down just untill your elbows lock then drop 100% of your weight on it with arms locked. Yup that easy.
The only pump "I": had that was junk was the AF.
Lot's of good fill informtion in the compressor section.
John