I have a Searcy in .500 Nitro, but I must be realistic about the fact that if the airline loses my ammo suitcase, then I will probably be unable to find replacement ammo. The chance of finding replacement ammo for a .470 is much greater.

Also you may want to consider recoil. My .500 kicks a lot more than the .470's that I have shot. It is enough of a difference that I think most shooters will be better marksmen with a .470.

As for a .577, the rifles are just too heavy to take on long stalks at a rapid walking pace. So I would stick to either .470 or .500.

Good luck!