"....For those of you that do hunt Africa and do actually shoot honest big bore rifles on a "regular" basis what do you prefer?"
Again, if you truly want a discussion of this question by those that walk the walk, then you must go to where those individuals are. Go to accuratereloading.com in either the African or Big Bore section. Otherwise, here, you are working almost entirely with conjecture.
If you mention you have a 338 RUM I expectmost would not recommend a 375 H&H to you.