Rdog -
I have a .375 Ruger used on one safari in RSA and two seasons of deer hunting. I have not yet acquired an H&H. Either will work.
I prefer the Ruger (in a Ruger stainless Alaskan with 20" barrel) due to the standard length action shaving a bit if weight off, the Hogue overmold stock absorbing some recoil and providing a straight-line recoil. I gladly surrender 100'/second to get to a 20" barrel for handiness. I still push a 270 grain Barnes at 2611 FPS, so have perfectly adequate power going downrange. The accuracy of mine is wholly adequate to shots at least out to 253 yards on an old blesbock.
BTW - I also have a Ruger Alaskan in .416 Ruger that shoots 5 shot groups under an inch at 100 yards. (I needed another hole in my head, don't you know...). That one borders on too much of a good thing, so I wear a sissy pad to avoid developing a flinch. I never needed one with the .495 A-Square, but the recoil on the Ruger is a bit quicker. Perhaps some extra weight added to the stock is in order? They are fairly light for the cartridge. This begs to remind you that the overall package matters.
I have M-1 Garands and pictures of P-51Ds for nostalgia vs. the 375 H&H. Since I was starting fresh (didn't have anything larger than a .35WAI), I went with the newer, more modern cartridge.
Since there are many things that will stomp you into toe jam or run you through over in Africa, I chose the handier/more compact package. I carried the rifle alot more than I shot it on the trip, so I appreciated not lugging the extra 4"-6" of rifle barrel through the thorn bushes. Will you hunt in Namibia? If so, then the extra length of the standard H&H arrangement will not really be an issue due to the open nature of the terrain.
As I study Boddington and Robertson, consult with Woods, I keep getting told that 20"-22" barrels are the way to go. LPVO is the way to go. Training to shoot quickly off the sticks and field positions with quick follow-up rounds is the way to go. I feel the Ruger facilitates this.
Working the bugs out of a Mauser (Zastava) has it's rewards. Perhaps the perfect answer is, as one of us above quipped, to get both. : )