Bigmaxx,

Given the choices you have available, I'd add the 375H&H as my second gun for the same reasons several others have mentioned. It can function as your buffalo rifle if something happens to the .458, yet is flat shooting enough for the plainsgame you mention. At least in Zim, where you won't find many long distance shots. Although the likelihood of something going wrong with your .458 is slight, it can happen. I seem to recall it happened with our NE member Larcher in Zim last year.

As for borrowing guns, I personally think I'd take the chance of bringing my own. I'm never completely at ease with borrowed guns as compared to my own rifles which I have practiced with endlessly prior to the hunt. Loaner guns can be excellent, but they can also be complete dogs. So at least find out beforehand what you will have available.

Erik