Thinking about it, it might not be so relevant.
Let’s say you finish an Anchor and want to use an 85% TM for your next program.
You up the TM 5-10 pounds from the Anchor TM:
-if you get 5 solid reps, you’re good to go, that’s your 85% TM
-if you get 4 solid reps, stick with the TM you used in the Anchor
-if you get 3 solid reps, that’s your 90% TM, take 5% off and you get the 85% TM (you could test it at the moment, after you get 3 reps, take 5% off, rest and see if you get 5 solid reps)
As sufiandy said, even without PR sets you’ll get some feedback about your numbers during the workouts, so you should never end doing only 1-2 solid reps with your TM - if that happens, you fucked up badly, at that point I guess it would be better to go back 2 cycles with the TM and possibly re-test the lower TM at the moment.
Sounds like a reasonable approach enough?