I felt I should exercise the bow a bit more and it would be nice to see a force draw curve, but how to jot down figures without leaving the bow under tension?
Ha! Video it! Then play it back slowly and take off figures as required at one's leisure.
Easier in theory than practice, my lights were glaring rather on the scale, but by careful comparison I can see it came back to over 140# at about 31"
It's been a long day, and I don't want to mess up, so I quit there. I think the method has potential.
Here's a still grabbed from the video. Note the tape with a black mark on the scale is at 100# and the heavier line on the rule is 28"