You asked for loads specifically for the S&W 460 XVR AND wanted to know the "best bullet and load" for Deer and Elk. When you ask such specific questions you aren't going to get that many answers.
I have used Barnes Buster bullets over A 1680 in my S&W 460 though I've never shot an animal with them. Their construction is very heavy with only a tiny hole in the nose thereof. As you may know, armor piercing bullets are illegal to use in handguns so a heavily constructed bullet with a small hole in the nose was as close as Barnes could come to making a solid suitable for things like Cape Buffalo without breaking the law. While I have little doubt they'll kill a Deer or Elk that's not really what they're made for.
I've killed quite a few animals including Zebra and Red Hartebeest on the large end with an Encore 460 S&W Magnum loaded with 250 gr. Hornady SST/ML bullets over 2400. I also shot a deer with them; a European Fallow Deer and they worked very well. I have little doubt they would work well on Whitetail Deer and Elk.
I've used a Hornady bullet similar to the Hornady SST/ML bullet; the 44 caliber 265 gr. FTX bullet in a 444 Marlin Encore handgun to take things like Kudu and Blue Wildebeest and they worked well in that application. I used Hornady 300 gr. XTP Mag bullets in my 460 S&W revolver on a Grizzly with good results as well.
So, there are a variety of bullets you can use in your 460. The one I would go with for a revolver would be the Hornady 300 gr. XTP Mag.
By the way, I've tried H110/Win. 296 powder with a number of bullets in my 460 and never got the best results with it.