In reply to givemetea:
What exactly are you trying to quantify and what equipment do you have available? Are you looking to measure how how a certain training regime affects climbing performance or how that regime affects specific grip and limb strength measurements?
For the former I'd maybe look to set a number of problems on a board then either alter the board angle or the ballast the climber carries to make the problems progressively harder. Obviously you need to be systematic about things like equipment used, rest intervals and hold condition. Then repeat the experiment after training. The problem with that is that the first session is on new problems, the second session is on familiar ones, you might expect an improvement even with no training (control group needed or a couple of familiarisation sessions before taking your baseline measurements?).
For the simpler grip-strength test I'd instrument a set of holds or fingerboard (could be as simple as standing a ballasted climber on scales beneath the board) then have them bear down on various grips.
jk