Resetting TM After an Injury

I picked up an injury in my elbow a few weeks ago and have not rained upper body for 3 week and I’m wondering what I should do with my Training max.

Background

Have been messing around with training e.g. P90x, insanity and other home (non-barbell workouts for a couple of years)

Started a program called Mike Matthews one year challenge - centred around compound lifts plus 4-6 other exercises all 4-6 reps as heavy as possible

After 3 months of this plus a lot of hiit I started to plateau and feel really worn out.

Discovered 531 and have decided this is the way forward, have seen the error of my ways!

I’m 34 and I suppose in the scheme of training where everyone else who follows sensible programming is I’m am still a beginner having a serious training age of around 3 months.

My injury is pretty much good to go and I plan to start 531 tomorrow

3 cycles of 5s pro with 5x5 fsl
plus push / pull / abs 50-100 reps for assistance

2 cycles of rep PRs with 3x5 fsl
plus push / pull / abs 50-100 reps

Agile 8 daily
Incorporate box jumps and throws
4x 30 mins easy conditioning either easy run or bike - looking to build a strong aerobic base before adding in harder conditioning

I worked out my TM based of my lifts from a month ago but being a training beginner I’m not sure where to start from now as I’m sure I’ll have lost some strength.

I was thinking that I should reset using my training max as my new 1RM and then recalculate 90% from there, or should I use 85% of 1RM?

I know the 7th week protocol is me ruined a lot on here but I can’t find enough details to understand what is going on properly. I know the new book is about to be released and plan to buy it when it is.

Another quick question - what’s the current thinking on supersetting pull-ups? Are these reps counted as the pull part of assistance work or are they added in on top of that.

Any other suggestions gladly welcomed. Thanks.

I count supersetted pull-ups as part of the total number.

If in doubt, go with the lower % of TM.