I really don't see that the 460 Wby is "overkill" on elk. Maybe that's because the only game I ever shot with mine was PA groundhogs.
Naturally you want to make sure than you have an adequate backstop (mountain) just in case you get a complete pass-through.
When loading the 460 Wby for groundhogs I found the Hornady 300gr HP bullet to work just fine. For elk I'd move up to the Hornady 350gr FP or RN.
I have shot quite a few factory 500 grainers but couldn't continue due to the high cost of chiropractic care. LMAO