If you think about it in terms of how ACS works, there could be something too it. Theres bound to be a smidge of concave, or at least flatness to the back, and I've always held the notion osage rings behave as laminates under strain. I'd imagine with care and the right specimen the back ring could be made sound enough, particularly with sinew and in light of Timo's recent experience using quarter or rift sawn osage as a backing. There was a time I would have predicted the back ring would fail, but this could be an interesting project. But the effect, or advantage, may not be so pronounced as to be revealed in a typical design and/or crafting.