More Americans bring and use a 300 mags then all calibers combined. I have as a loaner a 30/06 which has taken several hundred aniamls for myslef and my clients. We have never lost a single one with this cartridge and 165 grain premium bonded bullets.
I like the little 30/06 quite a lot as its very light, no recoil, and has enough power to sort out any plains game you will come across. As far as DG just leave it be. Nothing smaller then a 458 caliber can be considered a serious stopper under bad conditions, and nothing under 375 can be considered a practical hunting choice. YOur The need to pack around a stopper for a recreational sportsman is zero and would be silly to attempt. Beleive me I have plenty of very paranoid hunters dragging a 13 pound "stopper" around on plains game hunts. They are miserable after a few days hunting and we usually sit up at a water hole after that.
We should keep the perspective of a hunting gun and a back-up "insurance" policy seperate. The two guns cannot be combined into one. You will be with a PH for a good reason. Your focus on hunting should be on the desired species, let the PH worry about any problems that come up. Its what your paying him for. Odds are far greater you will have more life threating issues on the drive to the airport then you will with an irate DG animal in Africa.