Want some really sane advice?
If you're gonna invest Safari money in a trip to Africa, then just go ahead and buy or borrow a .300 Win mag to take with you.
Heck even an old flatback sporter will get the job done very effectively and can be picked up for around $300 if budget is a problem. You can always get your $ back when you get home.
Zebra can double and Eland can quadruple the size of a wildebeest very easily.
What's too much gun around here, can quickly become marginal there.
also I wouldn't want to drag around anything with a heavy barrel like a tactical rifle.