Personally, I can only tell whether the back tension was right or not AFTER the shot. I used to be able to feel it during the shot, but not any more.
The follow-through that I get from good back tension (both recurve and compound) is:
- drawing hand stays close to the head and moves a few inches back
- drawing arm stays in the same shape as before release
- bow arm moves back and down
It's then a matter of trying to replicate the shape and dynamics that produced that result. Took me ages.