I only have the two, one for gas and one as a back up. I do use a catch can with my electric and I don't seem to go dead stick or run out of fuel during flight. I just haven't found any advantage to crank pumps. I don't care for the six shooters at all. IF, a big IF they made a high volume crank pump I would switch over, say 10 cranks to fill a 16 ounce tank. When I fill one of my gassers with a 20 ounce tank it just goes on forever!