RE: back tension release and a solid back wall
I can't get good back tension without a solid back wall.
If I were shooting a bow with 55% letoff, I think I could do it, but I have to have something to pull against at full draw in order to get my release arm scapula to work right.
There are several different techniques for shooting back tension and they all require a little different set up from the equipment.
Since you are in Pennsylvania, I recommend that you take Larry's class at Lancaster Archery to start back tension. Larry also give private lessons at his home. A good coach like Larry will save you a lot of time learning BT.
Good luck,
Allen