I used Black Hills Ammunition, .45-70, 405gr FPL. So, I would think any modern bullet would meet or exceed the performance of that round. I agree with, "Use what works in the rifle and what you're comfortable with."
I have a box of 220 Partitions looking for work.
"Generally" the folks I know that have done it "brained" them. If that's the plan, either of the 2 you mentioned will work.
I've used the Accubond, and been happy with them.
Were it my hunt I'd do the brain shot also. However many private hunts won't allow head shot in fear of the Hunter not only killing the buff, but knocking off a horn in the process resulting in the hunter demanding a shot at another animal.
If his is accurate with the 215 Hybrids, I wouldn't change it up right before a big hunt.
Buffalo are thick-skinned and should have no problem making that 215's jacket open up. Make sure the tips aren't clogged before the hunt. I do that with every brand of HP hunting bullet I use.
I hadn't heard that before.