Mike O’Hearn’s Power Bodybuilding: Back Workout

From what I've read about the program; it usually states "max weight"

From that, I think we can determine he means from where you're at in the program, you should do your 4repmax (4rm) or 3rm or 2rm.

But from how it's done in the videos, it always looks like he's increasing weight drastically, adding a plate on each side after each set

The way this program explains it; Use the same weight for all 7 sets, but do a few warm up sets first(the warm up sets are when you're slowely increasing the weight). Rest at least 3-5 minutes in between sets. You're not trying to burn yourself out, you trying to lift as much weight as possible. Don't rest so long that you're no longer warmed up though.
Mike makes it very clear if you watch the video.. Take Your Time.

I actually asked Mike this same question because of how the video was edited. Just finished week for and each week my weights went up on my 7 sets. The 70% of 1rm suggested for first 4 weeks is pretty light considering your only doing 4 reps per. My four week progression on deadlifts have been
Week 1 335 7x4
Week 2 365 7x4
Week 3 385 7x4
Week 4 405 7x4
No getting around it those 7 sets aint easy but man youfeel good when your done. Drive on!!!

I agree with Leolll. This is how I do it.
Warm-Up:
60kg 6 rep, 80kg 4 rep, 100kg 2 reps, 120kg 2 reps, 140kg 2 reps

Working sets:
150kg 2 reps for the entire 7 sets with 5min break in between or as long as I need.

I am 5'5.5" and weigh 63.6kg. 150kg is incredibly heavy for me but not a one rep max. I can manage 4 clean reps on a good day.

3-5 minutes. You want to be well rested to destroy the heaviest weight you can on every set.

I agree with Leolll, take as long as you need to recover and than destroy the weights!! You shouldn't be thinking about going heavier after a few sets since that means you were taking it easy to begin. You shouldn't even drop the weights as you start to fatigue, just take longer breaks, drink fluids and recover before your next set.

I would suggest that you do as many low rep sets as you need to warm up. Even if this means lifting 3 reps of let's say 60,80,100,120kg before you start your working sets.
Once on your working set, choose the highest weight you can handle and power through the 7 sets. Take as much rest in between sets as you need. Most of it is a mental game. You destroy the weights, not the other way around.

The reps change throughout the program. I'd say 5 sets x 4 reps the first month, 6x3 the second month, and 7x2 the third.

If you managed 5 sets, 3 reps of 120kg you are doing it right. On the last few sets take longer breaks and make sure you are hydrated. Don't lower the weights just take time to recover, heck sip on some amino/electrolyte drinks. It gets tougher half way through the workout so remain head strong and motivated and watch your form.
I did 3 reps 7 sets of 140kg today and destroyed every set. On set 3 I lost focus and struggled so had to slap myself a few times to regain my focus. I weigh 60 kg.
You can do it!

The workouts are long, takes me over 2 hours to get through the exercises due to longer rest beaks. However lifting the heavy weights is rewarding and I am enjoying the poundage. The muscle fibers are demolished by the end of the workout so attention is required to recovering. Making definite gains in strength and muscle mass.
I find that I have to maintain a clean diet and concentrate on supplementing correctly to recover and make gains.
It's a great workout but you have to go in head strong and motivated, don;'t let the weights beat you and don't back off on the weights. Go heavy and go hard (after you have warmed up). Take as much time as you need to warm up and recover.

I find lifting heavy and eating an excess of clean calories helps me put on muscle. It's a slow progress but progress none the less. I have benefited from this type of program more than doing pyramid sets. I managed to put on 4kg of lean muscle and drop down to 8% body fat in 9 months on a caloric deficit. However now I eat 300 calories more than my BMR.
Best of luck with your training