Funny, I'm halfway through making the bow you describe, my first of this design. Its 71", elm, and the plan is to have it bending just little bit in the handle. I haven't measured anything, but I think the middle section is about 1,2" wide and the widest part of the limbs, about 15" from the center or so, probably around 1,5" wide. Kind of sharply narrowing from there and the outermost foot or so is slightly (I'm hoping gracefully) recurved, stiff and narrow. I'm aiming for 50 pounds at 28". Maybe I'll tiller it to 25 or so and the heat treat it. Or maybe I'll let a little bit of the recurves do some work. I'm not sure.
With 80" at your disposal, you've got plenty of length for a stiff handle. What draw length and weight are you aiming for?