Originally posted by McP
Well, I doubt that during the War, he had a time to learn. Not much. He was pursued by Jedi, and had a lot of work as a CIS leader. That could be tiresome, and he was 3 years older.
We know that he at least at one point in the Clone Wars grew in power, when studying Darth Andeddu's holocron. In Dark Rendezvous, which is near the end of the Clone Wars, we also see that his castle/villa on Vjun contains dozens of holocrons so I think it would be quit unlogical to have them there if he isn't going to use them.