I agree that ammo availability is not an important factor since I reload for all my guns, but the .470 has this advantage on her side, to be fair.
And I am sure the .500 has considerably more stopping power but on the other side the difference can`t be huge, and shot placement is what counts anyway.
After reading Your comments it looks like the .470 is the better choice.
Thank You Gentlemen

Kalunga

Wicked good hunting !!!