Yes, 8 year old thread and I still vote for pre 64 model 70 chambered in the grand ol 375 Holland and Holland. It will get the job done without any fuss at all. No worries there...
I agree with that. There's really no point in considering anything else.
If you shoot a buffalo in the chest with a .375 300 grain bullet it will run about 50 yards and die. If you shoot it anywhere else, you've got a problem no matter what you shoot it with. If it charges, you'd better break some bone. A .375 will do that. So will a .416.
As for elephant, a .375 300 grain solid at 2500 fps will penetrate both shoulders side to side of a big bull elephant. All anything else adds to that is recoil. Same for 350 grain bullets. For brain shots, it does not matter.
Often overlooked is that good shot placement is easier with lower recoil because you will flinch less.
I wonder if there is anyone who has shot a goodly sample of DG with both a .375 and a .416 and has noticed a difference. I have shot a buff, and elephant, and a hippo with a .458 and also one each with a .375. Small sample size but I could tell no difference.