That's a wonderful bow, Druid!
I have never made an elm bow that heavy weight, or that long, but I have made a few around 60-70 lbs in the 67-70" range, sometimes with lots of knots.
I know you don't need MY advice, but I have good success and low set if I get a good, even, but not extreme bend in the middle of the bow. Then, I let the outer 1/3 of the limbs get just a little soft, almost whippy, then stiff again the last 10 cm or so.
At first I was under-bending the outer limbs is all, I think.