This post is hitting close to home for me.
As previously stated I have used my 450 No2 and my 9,3x74R [scoped] on 2 previous Safaris with excellent results.
On my next trip I am taking my wife.

She plans to use a 450/400 3 1/4" on cow elephant, buff and giraffe, eland and a 308 Blaser for plains game. I was planning on taking my Blaser Safari 375 H&H as she could also use it if necessary.[The 450 No2 goes of course].

Since I have used the 9,3 quite a bit I thought I would give the 375 a go so I can see if there is any difference between it and a 9,3 and also see the difference when using a bolt action.
I have never used a bolt rifle in Africa.

However I am having a hard time making the decision on which one to take.

The Chapuis 9,3x74R double has been perfect... in every way.