I found Barnes #3 manual data to work well for me.
They list data for the 450gr. at 2,280fps using 63gr. H4198, an ADI powder and 62gr. H4198 for the 500gr. at 2,168fps.
Mind you, that was with the non-banded bullets. My .458 Alaskan did those speeds with normal lead core Hornady
jacketed bullets, same loads. I was easily making another 50fps with the slower IMR 4895, but I assume H4895 would easily
duplicate that or even improve it.