As others have said, harness tether isn't the issue, just lower your tree strap. I don't use the one the comes with the HSS vests, instead option for the prussic system that they sell. The prussic system has a longer rope for around the tree, and you can adjust it infinitely to suit you best. I set mine so that when I sit down, there is just a little bit of slack in the tether from my vest. You can do this in the yard just with a chair sitting on the ground to get a feel for where you want your tree strap in relation to your height, like say you put the strap 6" above your eyes, or something like that.