As you are requiring two rifles, I'd say a 300 Win Mag+ another 300 WinMag.
Joking asidet, any rifle different from the 7 or 300 Mags is becoming too specialized and then inappropriate for some games or others.
Most of African games are surprisingly tough. I'd feel undergunned not using a magnum. On plains one could have to shoot beyond 200 yards, thus a flat shooting magnum again.
My choice would be the 300 WM (or 7RM or 30Wby or a short magnum) and as a back up exactly the same rifle-calibre............or an accurate cute 243 or 22-250................just cause small is beautiful.
But...........................in Africa and letting my 375HH home would be anticlimatic.
No I'd bring a 300 WM and a 375HH.