Justine--I'm not sure exactly how much you should increase your weights between the sets. Last week was my first week and I am not really "counting" it since I feel like I was discovering the weights I need to use. This week I feel officially starts the rotation for me so I will add an extra week to the first phase.
With that said, here is the conundrum I noticed with these workouts--for me at least. Sagi heavies up a lot (his crew not so much--but then Sagi rarely does every rep and never does every set) and I can't do the kind of big jumps in weight between sets that he does (but look at him--DUH). The first set is more an endurance set so I use moderate weights. My jumps right now are 5-10 pounds between sets depending on the exercise (sometimes even less for things like shoulders, biceps and triceps). I do feel like for that final 8 rep set I should be able to do a bigger jump than what I do--but here is the issue--the tempo of his reps is brisk. Too brisk for super heavy weights (for me at least). Now, due to the fact he almost always gives you some sort of break between sets, you'd think you could go a little slower than he does and therefore be able to go heavier, right? You still have that rest period between sets to finish up before moving onto the next exercise. Wrong. Many of the pyramids end with a drop set. So you pound out 8 heavy reps fast, drop them and grab a lighter weight (with like 6 seconds between the heavy set and the drop set--just enough time to set down dumbbells and grab another set) and do the fast paced 8 rep drop set. So basically, I felt rushed with these and as if I needed to chose my weight so I could get the full 8 reps out and also do the drop set.
I'm still working on how I want to handle this btw. His workouts are shorter than what I am accustomed to, so using the pause button could be in order (though I have some weird aversion to using the pause button during workouts). Last week was my first week. This week I'll be using heavier/more appropriate weights and I can also get a better idea on how I want to handle those final sets in the pyramids.
Today was my second time doing Legs and since I heavied up this time I feel like I got an even better workout (though I won't lie--I got DOMS last week from Legs). But like you, Justine, these workouts (except Tempo) haven't been wearing me out. I do feel like they give me a good workout, but I feel like I could do more when I'm done. Maybe not more strength in the muscle group worked, but I could easily add on cardio. Today I did X10 Cardio Blast after I finish Legs, then topped it off with the stretch from Cardio Leg Blast. It was overall a great workout.