After searching through the codes and adjusting them here and there, I've concluded that trying to adjust the drills to always be Great is a royal pain -_-
The codes I've adjusted seem to be random most of the time, yet during the drill they always become either 0, 1, 2, or 3 and represent Fail, Success, Great, and Cheat respectively (maybe 4 is Trauncy, but I haven't come across that result).
The best I've managed to do is get "Great!" to pop-up on the screen and have Colt ask whether or not you want to praise it on light drills. However, the stat gains always reflect the ACTUAL results, not Great results (which is funny because if your monster fails/truants the results show +0 and Colt still says it "did its best"). If I try this on heavy drills the game freezes :/
I'd rather just call it quits and say it's all rng (random number generator) and there is no way to accurately find the correct codes unless one of the original programmers actually pointed them out and explained how they work. In my opinion if you're going to hack the game to change the results of the drills you may as well just change the stats of the monster instead, it's less of a headache.