Alternative opinion...
Ditch the standard harness
Get a rock climbing harness. $50 At rei. Works great. More comfortable. Easier to put on. And if you fall you'll be facing the tree. So self rescue will be easier. Also works great for hanging stands.
Figure yourself out a rope system that attaches to the tree and your good.
I use 11 mm pmi static rope as the main line, and 5mm pmi accessory line for my prusik knots.
I make a loop at the end. Tie two prusiks onto the line. I put one caribeener at the top prusik. Wrap the loop around the tree, adjust the prusik and connect the caribeener. Tighten. Attach the other caribeener to the lower prusik. I use a short length of some sort of shock absorbing rope that goes from the harness to the lower caribeener.
So there's 2 points of adjustment. So it's easy to adjust the system to be the proper length given different trees.
If any of that makes sense