I think you are blatantly overthinking to try maximise progress in the short term. But I do like a hearty discussion and you've clearly thought about this alot and it's something I have never considered.
So to clarify, you are proposing to adjust your TM to 90% of the highest e1rm you achieve in a given cycle for each lift when calculating your new weights for the next cycle? As Opposed to standard consistent incremention as described in the program. And you would like to do this consistently every cycle?
E.g. (We will use a TM of 100 to keep it simple)
TM 100: OH Press
Highest rep record 95*8 = e1rm of 120
New TM = 100+10
New TM = 120*0.9=108
I think this is a flawed method for a variety of reasons.
Firstly, the formula used to find a e1rm, does just what it says. It estimates. It is not to be used to say, "yea I can bench 315," because your e1rm says you can but you've never done it. It is simply a tool used to standardise and COMPARE rep records. You will also have 3 e1rm's for a given lift each cycle, I assume you propose to pick your best record, which isn't necessarily reflective of actual ability and the reps you get on each day are highly dependent upon feel and mood. Your e1rm from week 1 could be the highest and now you want to adjust to that when your most recent 2 weeks you couldn't make it to that level. You may have busted out 2 extra reps on the deadlift cause you had too much pre workout or some shit and didn't realse your back was out of neutral and now you start your new cycle and your back can't take it.This is a silly example but the point is they are highly subject to variability and are not used for ANY reason in 531 other than comparing rep records.
Secondly you are putting alot of faith in the 90% and it seems you think doing this will prevent you from stalling longer than normal. Firstly the rule to drop back to 90% when you stall is kind of outdated. The genral rule is to drop the TM 2 cycles worth. And moreover saw the rise in popularity of the 5 cycles forward, 3 back rule of keeping consistent progress. And one of your prime justifications for this is that you may progress even LESS than using standard incrementation, to try and show that you are not just trying to progress quicker than normal when lets be real, you are, that's the point of starting this thread. Let's just call it what it is. But if you program your starting TM's correctly to 90%, current recommendations suggest even starting 85% or lower in some cases, then there is almost no scenario in which using 90% of the e1rm's you initially get won't result in a LARGER increase than the standard incrementation. E.g. if you program it correctly and 100 is a TRUE 90% of 1rm. It is standard practice for those using true 90% to achieve 12-15 reps on 5+. Using the lower number with your method would still result in a jump of 7.5 as opposed 5 with standard incrementation.
Lastly this won't necessarily fall in line with the basic principles of the program. Start too light, progress slowly etc. and make consistent progress. Doing this is inconsistent. I've already established that each e1rm is essentially arbitrary so one month you may jump 10, one 5 and one 20 dependent on how you did and how you were feeling. Inconsistent jumps lead to poor form, which leads to breakdown, which leads to failure. The purpose of 531 is to be simple and straightforward. You are adding unnecessary complication which will fuck you up in the long run. If you keep it slow and keep it consistent this is how you make sure you squat is always to depth and your knees don't buckle i.e. you body stays stable and knows what it's doing.
Also Jim clearly states in ALL of his books that if you're e1rm is way higher DON'T change it, the program is working. You could probably just read that.
This is probably full of typos, I have really bad eyes