I braced mine in several ways. In the end I ended up with a strange ultracase 9".
I took the 8 3/4 as far as it would go. It was back braced, load bolt supported, and the most important(in my opinion) was the internal bracing that went right up to the caps so they could not spread. After the internal supports, the teeth didn't break anymore. got me through a season of racing. low 9s at 3700 pounds with a trans brake. Started working on the 60' and started shearing pinion shafts. No patch for that!
Went with a 35 spline pinion ultracase and put the whole rear end doubt right out of my mind.
That said, with a lighter car, I probably wouldn't have needed to switch. It was a lot of work though.
I don't have any pics of the internal bracing.
My thoughts exactly with the bolts. I would do a brace inside like a can with no top or bottom that spaced from front flange to the back one, then holes drilled for axels. If there where some bearing with less taper to replace the back pinion bearing, or even bronze bushings like a metal lathe, would help on pinion deflection.
