If you're buying them (not casting them yourself) ask the people who make them what data they use or recommend. I've never used that weight, so I have no idea what a good load would be.
I would assume the powders normally used for 405gr and 500gr would be suitable, which one is "best" is always determined by the rifle being used, if it shows any preference in accuracy for a particular powder over others. Some do, some, not so much.