The 450/400 3" would be my first choice. The 375 H&H has killed a bunch of game and killed it dead. Compared to x-sectional area bigger is better.

I have a 450/400 3.25" and it is great. The problem is finding brass. I lucked out and walked into a local gun shop and found a box of Woodleighs in soft point round nose 400 grains! I will never walk into a gun store in Anchorage and find 3.25" brass...dream on.

If you threw 450 #2 in there, I would change my vote. Now talk about easy to find bullets and very hard to find brass! Those are the facts and the draw backs. There is no free ride.