The good thing about strength is you can get stronger even while losing muscle. Powerlifters do it all the time in order to go down a weight class. Doing triples instead of 10 reps.So here's your problem (there are climbing guys in the grip community): It's a power to bodyweight ratio issue. In order to be a better more able climber you wanna lose hard earned muscle. Normally I'd suggest getting stronger but you are already a powerlifter. And we can't suggest losing fat cos your already pretty lean. So muscle it is