Hypertrophy I - RPE Guidance for exercises that use e1RM % AMRAP?

On days 2 and 3 of the Hypertrophy I template, it calls for the following:
70% e1rm x AMRAP x 1
63% e1rm x 12 x 2

What’s the recommended approach for an exercise you haven’t done before, and thus don’t have an e1rm? Using the RPE table, I inferred 70% was roughly 10 reps @ 9, so I did warm ups until I hit that RPE and considered that to be my 70% AMRAP. But when I went down to the supposed 63%, I was barely able to hit 10 reps, and had to drop significant weight to get to a 12 set rep that wasn’t a grinder.

Any feedback on my approach and what could’ve gone wrong? Thanks a lot!

In general, 70% is ~ a 10RM so you’d pick a load you predict will get you to failure around 10-12 reps. If you do <8 reps you were a bit too heavy (or not well-conditioned for the task) and if you get >12 reps you were a bit too light (or very well-conditioned for the task). Sounds like you were a little heavy from the jump and then needed to go a hair lighter, plus or minus any conditioning effects.

I’d go a bit lighter on your AMRAP set next time.