The calibre choice is alway as debatable as the preferred vehicle brand and best tyre to do offroading....
Being a leathered PH and listening to conversations around the campfires on our safaris, you gather a lot of advice and get to poke a couple of suggestions around and feel the response coming from clients.
Shotplacement is the best choice.....just another opinion , but once you can deliver a very well placed shot with trustworthy bullets, the calibre choice is up to you.
My BRNO .375H&H have proven itself over and over. My Mauser .458Lott is my go to as back-up , but experience and bullet choice cannot be placed on the back burner.
On Elle, a lot can go wrong if your bullet do not have the penetration that is needed. The tusks inside the scull is a major obstruction and the nasal cavity alike.
If you hit the brain with a .375 solid, you will have the trophy on the ground......missing the brain or spine with the biggest rifle , may leave you on a death run or ending up under the tusks or trunk of a wounded Elle.
I use Peregrine VRG3 Bushmaster bullets on all DG hunts with excellent penetration, perfect expansion and proper weight retension.
" HORSES FOR CAUSES " , Budget is also a prominent factor.
In short : Why use the minimum calibre if your life is at stake ? Rather get a rifle that gel with you, not kicking like a mule. A calibre that you can handle and shoot from the sticks and still do a 50-80 yard 5 shot grouping into a 3inch circle. Use good ammo and study the anatomy of your trophy while putting you in every possible position to take a shot...........Your first shot determine the type of funeral in camp.....yours or the Elle's funeral.
The most common mistake on calibre that I have seen, is the biggest, heaviest ass kicking rifle to boost your ego in the gunshop or around the campfire..........We see this so many times , use enough gun, be one with your rifle, use it as your companion and do not let your ego choose your calibre....