Just as I stated in my previous post, I do knot own a 460, so can only rely on secondhand information. The figures I gave were simply what was revealed in a very quick Google search.
As for what your load and gun do in comparison with the load I quoted, you gain about a 4" advantage in trajectory and about 500 lb ft of energy, a much bigger gain in terminal energy at the 200 yard mark. Thus my preference for heavy for caliber bullets.
You are correct that I set the zero range at fifty yards. For comparison purposes, the sight in range doesn't matter as long as they are all the same. Fifty yards if where my guns are sighted in, so that is the number I used. There are a variety of ways to determine "point blank range" zeroing distance to accomplish exactly what you are talking about. Just a "SWAG" (Scientific Wild A** Guess), I would think that if you zero about 3 3/4" high at 100 yards, you would have a dead hold about to close to 200 yards. If you know the bullet and actual velocity that you load and gun combination deliver, I can plug in your numbers and post the info for you.