Is it better to do a single top set everything week or stick at one weight for all sets ?
It depends, I would say you’re going to want to use both approaches at different points of the year. Typically I’ll do straight sets (same weight) most of the year to build up some work capacity and refine technique, and then when I’m peaking, typically for a meet, I’ll do more of a pyramid approach where you work up to 1 or 2 true tops sets on the main work. Another option is to use one approach for your A movement and the other for your B movement within the same workout.
Basically you just want your final set to be at the RPE that’s prescribed in the book. If you’re doing a 5×5 and around set 3 it feels challenging, you feel like if you increase the weight you’ll put forth more effort than you should be, but if you keep the weight the same by set 5 you’ll be right on the money, don’t increase the weight. On the other hand, if you’ve got some extra in the tank and know that if you bumped it up a little for the final set it’ll be the effort you’re supposed to be at, do that…. Part of it can depend on where you are in the program, it’s usually easier with a 5×5 RPE 6 to keep the weight in set 1 to be relatively similar to set 5, whereas 2×2 RPE 8 would demand more warming up, and your only be able to hit that weight at that effort for 1, maybe 2 sets max.