375H&H is always a good choice. .338 Win Mag is a little on the small side if you happen to meet a grizzly bear. The .375 Ruger will work fine but make sure to take plenty of ammo it is a little hard to find sometimes. The .416 Ruger is the same as ammo can be harder yet to find plus the recoil is something that needs to be worked up to. Most people find it more than acceptable.