Hey Im having trouble finding the post where you explain the harness system you use. Its really hard on my gimp knee when I drag the yak . I figure if I spread the weight around more it will make things better. I had your number in my old phone and for some reason it didnt transfer over to my current one.
I took the shoulder harness off one of my old golf bags. I run it through the front handle and drag it with my shoulders. I don't think it will take pressure off your knee, it was more to alleviate the wear and tear on my hands and arms.