As I read through this thread, what stands out to me other than size, is the fabrics. I don't see any hammocks listed made out of 1.6, 1.1, 1.0, M90, etc.
What I do see (I think...since I don't have most of these) are 1.9 oz (and up) fabrics, some of which are polyester and several are probably taffeta's or something other than ripstop.
I suspect body shape and mass distribution play a roll in calf ridge pressure as well. I theorize that concentrated mass in the center (think fat azz like me), stretches a band down the center making a tighter ridge that may be less able to form with heavier fabrics.
Just my thoughts and worth ~$0.02 as usual.