A trip to Africa is the treat of a lifetime for many and you all know enough to know that just about any of the legal combo's will work and you always have your PH to fall back on to confirm any info you learn from external sources.
My advice is to take the rifle that pleases you so you can focus on the enjoyment of the experience.
I personally would prefer a .458 caliber over a .416 for dangerous game so there is my choice. It has a lot to do with the rifle, the way it handles, feels to grasp and manouver if situations get tight. Your response time with follow up shots and the ability to place those shots accuractely, all of primary importance and way above cartridge choice.
As JB said, the quality soft points tear up a lot of flesh, break bone and penetrate well enough to make them the best choice for at least that first shot and I would be happy to also use them for the follow up shots. There is also the safety aspect to reduce the possibility of complete penetration when using a solid and wounding a second animal inadvertenly.
That aforementioned 450gn TSX is a super bullet that I feel is somewhat underated in the .458 case. I can load it to 2300-2350fps in my own .458 Model 70 and would be happy to use it on the larger bovines.
JW
