david, look at my bamboo backed osage: non-bending handle only 4 inches, no problem
I was going to pretiller my boards, too, but Gordon asked me "why tiller it twice?" so i just glued on the backing and then tillered it. On the other hand, i didn't put any reflex in it...
I am working on a reflexed osage/hickory right now with a built up riser, and what i;ve found is that the limbs bend in sort of a gullwing shape as they come off the handle. I didn't pre-tiller. Just glued a 9/16 piece of osage to a 3/16 piece of hickory in deep reflex. I am finding that the thicker the backing strip, the more reflex a bow will hold after tillering.
radius