It varies - the information's all available on the datasheet. Which actuator will or will not be suitable for a lifter I can't tell you, as that depends entirely on the actual design of your mechanism as to what input force is required to apply the required force to lift their robot. Work out what kind of shape you're aiming at, then what the mechanism will be to apply the required motion (whether a 4 bar mechanism or a simple hinged lifter, or whatever else) - then how much force you need to apply where in order to lift them.

Overvolting your lifter will increase speed significantly though, which you can get away with for low duty cycles.