I have taken 2 doubles to Africa on both of my Safaris.
A scoped 9,3x74R and a 450 No2.
On both trips I wish I had a shotgun or even better a drilling.
I now have a 12x12x30-06 Drilling with a S&B 1.1-4 scope. I think those 3 would be a great choice.

As for your original question I would be perfectly happy with the above 2 doubles and throw in my scoped [S&B 1.1-4 withj illuminated reticle] 450/400 3 1/4".