On all 3 of my Safaris I have taken 2 doubles.
A 450 No2 and a scoped Chapuis 9,3x74R. They performed perfectly.

On my last Safari my wife went as well. She took a Blaser R 93 in 308 and a scoped 450/400 3 1/4" double rifle.

I used the 450/400 for the first 15 days as I wanted to shoot an elephant and cape buff with it as well, so I could say, I have taken buff and elephant with all 3 of my doubles.

She used it on a Monster cape buff.

I also took a warthog, zebra, some baboons and a lion with the 400 as well.

IMHO, a scoped medium bore double and a 400 and up double make a perfect pair.

PERFECT IN EVERY WAY.