I think that it is a good idea to go ahead and take two rifles as well. I did, and was really glad. Lots of things can happen. stocks can crack, sights get damaged, mechanical parts break. And of course you can have each rifle suited to the game you are hunting. Hunting impala with a .458 will work, but kind of like swatting flies with a sledge hammer. I think you said at the start of this post that you had a .458 lott and .375, well thats perfect. I took much the same combination and found it to work very well.