I also found that increasing my draw (moving anchor back) just a bit allows me much better alignment and back tension. I believe that proper alignment is the key to good back tension.
Same anchor point doesn't work for all of us I guess. Different physiology; arm length, neck lengths, head size and all that.
This may not be traditional in nature, but I was tutored on back tension by a fellow who had one of those fancy tension releases. It really worked and is a real eye opener as to how it should feel.
As far as keeping it ? ..... I dunno, I'm certainly far from expert, and my shooting form ebbs and flows through the years, but I think if you study Terry's alignment clock, and watch some of the form critique videos you'll be well on your way.
Good luck !