Though I love the tradition and mystique with the cartridges and rifles carrying the H&H label, I'd go with the 416 Rigby.

The reason being the variety of bullets available for the 416 group compared to what is offered in the 411 group. If your rifle shoots the 400 grain Woodleighs really well, the 411 diameter is fine, but if not, its a bit of trouble to find other bullets.

I'm going through this process with my 411 Hawk. The rifle does shoot the 400 grain Woodleighs, but I also want something in the 350 grain weight also. I've horded all the Swift A Frames and Barnes X's I can find, but pickings are mighty slim. North Fork is developing a 360 grain offering in that diameter, but not on the market yet.

There's just too many good bullets in the .416 diameter for it not to be favored.