"So my main question is, once the bow's tiller is set and the profile looks good, should I just stay off the tree and pull the bow by hand from the 6 inch brace on up to my final draw length? I was taught to exercise the bow on the tree all the way to my final draw. I since then quit doing that and now I get the bow off the tree after it's reached the 20 inch draw length. Then finish by hand. SO how do you guys tiller a wooden bow?"
Roy, in my opinion, if your tree is set up properly and you’re using it properly, NO, stay on the tree until the end.
I can’t speak for anyone else that’s been helping you in your bow making, but what you typed in your initial post is not how or 'all' I taught you. It's not all about 'exercising' the bow on the tree after you reach a certain point of your draw length. I showed you to be critical of the bow’s tiller on the tree until you reach your intended draw length.
A bow's tiller isn't "set" because you reach 20" on the tree, or because the braced profile looks good early on. You should still be looking critically for flaws in the tiller, balance and harmony between the limbs, good nock point travel, how the limbs work into the dips equally and effectively, and more, anything and everything, at each inch of additional draw... all the way to the final inch. Are you doing that as you "pull the bow by hand"? Or are you just calling the tiller good at 20” and exercising it by hand a few times, an inch at a time, until you reach your anchor point? The flaws, the adjustments needing made, may be less obvious than those you find earlier on, but they're there, and you're missing them. I’m not talking about just little flat spots and hinges. Going 2/3 of the way may insure most of your bows won't outright break on you, but bows WILL reveal things to you in the tiller needing attention later in the draw, and if you're not looking for and correcting/adjusting them, your bows may be taking unnecessary set and not as efficient as they could be.
I continue to use the tillering tree until I reach my intended draw length and draw weight. I'm critical of every inch of limb in every way I can imagine, static and dynamic, at each additional inch of draw until I reach my draw length.
Don't get cocky or complacent with the tillering, Roy. The bows you're currently making, bamboo backed osage bows, by their own shape and construction methods, are easier to tiller, and tend to tiller early... meaning... if you do an exquisite job of the prep work, glue up, shaping, facets, etc, much of the work needing done that will affect tiller is done earlier in the process, and there's not AS MUCH to do in the last several inches of draw.... that's their nature. But you should still be looking. You'll find stuff needing done.
What worries me is, not all bows are like that. Many other types of wooden bows keep us on the edge of our seat, revealing idiosyncrasies and trying to sneak things by us right up to the very end... even AFTER you think you're done, they'll slide one in. That's why you have to stay on top of them, be critical of them, right up to the final inch, then shoot them in, and keep checking all the while, making any necessary adjustments and shooting and adjusting and shooting and… until THEN the tiller settles in… hopefully. Not all bows are as easy to tiller as BBO bows, even some of THEM can be funny. I’m just afraid for you, and anyone else that may be reading here, that may try to apply what you’re doing with your BBO bows, to an unruly selfbow, or a slightly psychotic sinewed recurve or something… and it won’t turn out as good as it could/should have.
But I digress, I tiller all of my bows (bamboo backed bows too) to full draw length and target draw weight on my tillering tree. My job, my desire, is to make each bow's tiller as good as I can possibly make it. I can't be assured of that if I'm only critical of it, and making adjustments for the first 2/3 of draw.