There are two prudent choices for this question.
First: ask your PH or outfitter his opinion on this. He is closest to the conditions and is the only one with first hand knowledge of the wY things will unfold for you
Second: call Barnes and ask them what the experience of their professional staff has on buffalo with these weights.
You can get plenty of opinions here, but none will carry the credibility or resolution that these will. For every guy posting one weight, there will be another suggesting the other.
It will become less clear for you then when you started this!
I can save you the phone call. Barnes will recommend the 270 gr in the .375, the 350 in the .416 and the 450 in the .458. Its not that they are "good enough", their position is that they better than the heavier "standard" weights.
