A .416 will sort you out properly on a DG hunt, however I'd like what other calibers you have. Most shooters have only experienced up to a .30 caliber magnum as their most potent cartridge. Moving from that to a .400+ is a major jump.
It is legal in all African countries to take Cape buffalo with a 375H&H or 375RUGER. If you have not experienced mid-bore recoil, I'd highly recommend this as a stepping stone to the .400's. Depending on how many DG hunts you plan on doing in your lifetime, you may find a .375 caliber more versatile than a .416.
As for brakes...no brakes. Your PH, tracker and rest of the hunting party will thank you. Practice with dry fire as much as possible to instill the proper technique and go to the range to confirm. This will not only save ammo and money, but your learning curve will be much faster.
Proper technique and rifle fit become more important as the caliber goes up. You can get away with a lot shooting a 22lr, but step into the realm of the big bores and you could end up scope cut, injured or develop a flinch you can't shake. Take your time and walk it up slowly.