I finally took the advice of the guru's here and dropped a bunch of weight to work on my form. I had been shooting a 56@28 longbow with decent results, but I felt like I was stuck. (that bow was actually a drop from a 70@29. I know, ouch.) I didn't FEEL overbowed, but my groups were only "good enough" not great. So, I got on the classifieds here and picked up an old Ben Pearson 35@28" and all I can say is I should have done it a long time ago. I'm shooting 600 grain arrows out of it, so it's pretty sluggish, but I finally feel like full back tension might be starting to develop. The proof is in the pudding; I've been consistently getting <3" groups at 20 yds. I'll give it a few more weeks of practice and then I'll get an update form video up.
Arne, Terry, and the rest of you masters, thanks a bunch for the free advice. Hopefully more of us younguns will start listening sooner!