I think it's tough to beat 7828ssc with what you're trying to do, but shooting an ELDx at Weatherby velocities, especially the 257, seems like asking an awful lot of the bullet. Unless you're really planning to stretch it out there, I'd recommend a mono. I prefer Hammers myself but have heard Barnes offers a really good one too. My Mark V shoots the 92gr HH at almost 3800fps with ES of 3 and stacks them into one hole. I think it's impossible to shoot a better bullet than Steve's creations for hunting, they do cost a little more but it's money saved when it comes to load work up. I load mine at 3.205''.
Good luck with whatever you decide. The 257 is a hell of a deer and coyote slayer!