This is the perfect conundrum for a hunter:
- Either will do the job just fine, therefor, no "wrong" choice
- Two is one, and one is none, so a spare could save your hunt - does the PH have spares there?
- Carrying 2 is more weight (potential charges of overweight) and hassle, two types of cartridges to split the 11 pound ammo allowance between
- Can you shoot each equally well? If the .416 is too much recoil, take the .375 - I would take a well-place shot from .375 over a shit shot from a .416 every day of the week and 7 times on Sunday! If you are fine with .416 recoil, I am with Napoleon - God is on the side of the larger battalion! Bigger amount of energy transfer, bigger diameter bleeding channel, bigger exit wound = easier tracking, quicker blood loss, quicker lung collapse, etc.
- Do you have "rifle love" considerations? My Ruger Alaskan in .375 Ruger is my Goldilocks rifle, but I would like to take my .495 A-Square to blood it as well. Illogical to take both as they overlap a great deal in capabilities, but it doesn't have to be logical - just make YOU happy.
You just have to feel your way through the pros and cons of each side of the choices, you lucky bastard! Have a great time!!!!!!