I've toyed around with the idea of getting a Primos sling for a long time... I
would love to not have to hold my bow on the long treks in to my stand; the problem is, my shoulders are usually taken up because of my stand on my back.
I've tried to sling a backpack over my shoulders when I'm packing my stand in, and I've found that usually one strap at a time is enough over them.
(Before anyone makes a smart-alecky remark, I've got a 33" waist and a 44" chest and can bench around 240... not bad for someone weighing 180; I don't think my shoulders being too small is the problem...

)