Some great advice I'm reading here.
I think if you really want a Magnum and think some future hunts can justify one I would go with the 7mm Remington Magnum. It will easy kill elk or moose,nothing more is needed,and the ammo is much cheaper and easier to find. If you happen to pop into a small town,population 1800,on your big hunt for more ammo,don't expect to find Weatherby ammo.For instance here in northern Canada there are only a few stores that carry it,but you can get 7mm ammo anywhere.
It would be really nice if you could try some shooting with an example of each,that might "seal the deal".
The record books, that are put out by Boone & Crocket and Pope & Young and where I live is Henry Kelsey they are a great way to research a state or a province for big game. This does take some time but the knowledge it gives you, can be very valuable. Not all hunters have their trophies recorded, as where I live after the Hanson Buck became the new world record typical Whitetail, we saw a flood of hunters and now that has happened, some hunters are shying away from the record books but...