They are all great choices however when you throw Africa in the mix things change a bit--
If you plan to hunt DG, then you will need to have a .375 or larger as it is the minimum legal caliber in most countries..

Following up on that thought---as I have mentioned many times on this site..I am a .416 fan..whether its Rigby, Remington or Taylor---You can load with lighter bullets if you wish--per the Barnes reloading manual..300 gr bullets with RL 15 and get over 2900 fps or load 400 gr bullets and get 2400 plus---in addition, the increased effect on game is noticable when compared to the .375...the same can be said when comparing the 416 to a 458...

I have a Sako in .375 and really like the gun and caliber --in fact if I were to go back to Alaska to hunt Brown Bear again I would probably use it as it is a model 75 stainless with a synthetic stock.. which would work quite will if "normal" Alaska weather were to prevail..however when I head to Africa the bolt that comes with has always been the .416...

The 404 Jeffery is also a great round however I have had very little experience with it--other than firing a rifle or two chambered in it ...

Good luck with your choice-should be fun..

Ripp