Gau: Automatic Rage Learning

I haven't yet, because testing it requires a new playthrough all the way up to being able to buy dried meat. I think I will though, to see if maybe I'm lucky and the description is inaccurate

EDIT: Now, reading Gi Nattak's last observation though, I could have him start with all enemies the party would normally fight up to the point of buying dried meat, and then the patch could take over. The only thing I don't like about this option is the bosses on the Rage list (how I'd have to have Gau in my party each time I fight any of them, which I believe is impossible). Is there a way to replace which monsters actually can be learned as a Rage? Then, I could have only "repeatable" battles on the list, and it would be completely fine for Gau to need to be in the party.