I tried 531 using the triumvirate model along with first set last and joker sets. I deloaded every 2 cycles as outlined in Beyond 531. I wasn’t able to make much progress.
As the weight increased my reps on the “as many reps as possible” set decreased. This is to be expected to an extent, however plugging the numbers into the 1RM equation showed I wasn’t really making progress.
A lot of people have reported great gains on this program. It was cool to be working with maximal weights. However, for me it seemed like the volume working at >80% 1RM was too low stimulate strength gains.