It has yet to be proven what exactly could be deflecting with a 8.75. I am not convinced the ring is not also a contributor here. On the pinion, it its double bearing widely spaced (relative to the 9" with no cantilever), although a small cantilever, the size/dia of the pinion shaft plays a role in deflection under load as its stiffness controls pinion off axis movement. Street tires I would be fine with 741, but any money invested is throwing it away, at least a 742 has resale value. I agree also on back brace is mainly cosmetic in this application. Might want to consider a DS safety loop if any of this advice is wrong.