@jellybug78 Here is a handy table for rep ranges for a given % of a TRUE 1RM (not a training max.)
I had no luck whatsoever following 5/3/1, and I do not think that 3 sets per lift per month working in these optimal rep ranges (note that none of the warmup sets come anywhere close to this range by any of the 3 models used in the linked table) is sufficient to drive adaptation if you are already reasonably strong.
For example, for a given lift on week one of 5/3/1, you would warm up with whatever you want, then are prescribed to hit 5 reps at 65% of your training max. This is actually ~59% of your true 1RM, which is a percentage too low to be addressed by 2 of the 3 models in the table above, and which you should be able to hit for 15 reps or more according to the 3rd model. This set is not likely to drive any gains in strength or size, as it is telling you to only hit 1/3rd (at best) of the volume you would need with this weight. This set is a warm up.
Your next set would then be 5 reps at 75% of your training max. This is actually ~68% of your true 1RM, and all 3 models suggest hitting that for at least 10 reps. This set is not likely to drive any gains in strength or size, as it is telling you to only hit 1/2 (at best) of the volume you would need with this weight. This set is another warm up.
Finally you get to your top set, which is 5+ at 85% of your training max. This is actually ~77% of your true 1RM, which should put you in the 7-9 rep range. So you blast out something like 10 reps and pat yourself on the back for making yet another "rep PR." Great. You've done one single set that was worth your time. Hope you made the most of it -- you won't be doing another one for a full 7 days! (14 days if you "de-load" every 4th week!)
Anyway, that's my 2 cents (again) on the 5/3/1 program. If it works for you, then great -- keep at it! But it is not a magical one-size-fits-all routine, and I absolutely floundered on it and got weaker.