Hi Matt, I tried that method of training, I think what you're talking about is the armstrong pull up program, It helped me to improve my endurance and my form, after months of training I realized I wasn't doing the pull ups with strict form (all the way down), now that I'm focusing more on my form and that's really helping me. I only worked the armstrong pull up program for 3 weeks and I didn't notice big changes, I should've worked on it for 1 month or 2 but I went for a vacation with my family (really I needed some rest haha).
I'd recommend you to do a pyramid workout to improve your endurance and strength. For instance:
5 pull ups 2 min rest
4 pull ups 1 min rest
3 pull ups 1 min rest
2 pull ups 30 sec rest
1 pull ups 30 sec rest
Then go back with the pyramid ( 1 pull up 30 sec rest, 2 pull ups 30 sec rest, 3 pull ups....)
Always with perfect form, remember that. Do this pyramid set before your pull routine.