Update: 5/3/1 is the ****.
Started the third cycle today and felt really great. I keep just upping the weight per the program, outdoing myself every week. The first week is always the toughest for me as it has the most volume on the main lift (3x5), but I still set a 1RM equal to or greater than anything I did the previous month. Crazy!
What I've also found effective for progressing the assistance exercises is to up the weight at the beginning of a cycle, then up the reps as the cycle continues.
Example: my squat assistance movements are front squat and walking dumbbell lunges, with squat jumps at the end to really tire me out. Last cycle I did 145 and 30 for the front squats and lunges respectively. This cycle, I'm doing 155 and 35. I do 3x8 this week at that weight, then next week is 3x9, then 3x10. If I'm successful at all of those sets for the movement this cycle, next cycle I'll bump up the weight again. If I fail one or more sets this cycle, I'll keep the weight the same next time. It's a great way to keep the assistance movements challenging while getting more volume on the days that the main lift volume is decreased.
Again, freaking love this program so far. Even with warmup before and stretching/a bit of cardio after, I'm in the gym for max. 1 hour and am tired after. Highly recommend.