Isn’t this fun! Well my brain hurts just thinking about this but I’ll take a stab at it! My guess is the middle one. I base this on purely my own experience with narrow bows vs wider limb bows and how much weight can be retained in draw with thickness in the belly vs width removal. The middle one looks little thinner then the top one and it’s also longer too which would lead me to believe it’s the 40 pounder. Now I hear what others are saying and I agree that a lot does depend on how a particular bow is tillered and build will determine much of this too. Set on all 3 seem fairly similar to me in the pics. The top two bows are about the same width to my eye with the top one maybe a little wider near the handle out of fades. It’s also little shorter too which was already pointed out so this sorta rules this one out for me. The fact that the all weight about the same in interesting too. Thickness does make a difference way more then width for poundage in draw so based on that I’m sticking with the middle one at 40#. So many variables to consider on this.