I think you are just fine with your current rounds/loads. Odds are, you will end up killing deer at much closer ranges than you will "get opportunity" for further out!
I love the .257 Weatherby, but the 25-06 gives up very little to it, as you know. I knew some 25-06 shooters in Texas ( years ago) and they all used the 87gr Hornady spire point. I had a 6mm/284 set up with the 90 NBT one year. I shot "at" an antelope doe at a lasered 527yds away. I was prone, I knew where to hold from practice, but that wind! She couldn't tell where the shots were coming from so just stood there I I shot 5 times! The wind blew it left/right/over her/under her! I quit before I gut shot the poor thing. I then drove around to a little secret valley I knew of on that ranch and popped one at 150yds! "Resist" the money pit of trying beat what you already have...all top flight rounds in their own right! ha
