You're going to shoot how far? 600 yds? If that's all the farther you're going to shoot then you don't need a custom. Custom rifles
are great but you can get a SAKO 85 for less than half of a custom and have a great 600 yd rifle. And when the barrel wears out in 10 or 20 years, you'll have a great SAKO action to build on with a custom barrel.
I know a guy with a Sako 75 300 WSM
who shoots 1/2 inch groups @ 200 yds with fed blue box ammo. It is easily a 600 yd rifle and potentially a 900 - 1000 yd rifle with the right bullet.
I agree with with getting real good glass. You could easily get by with an Elite 4200, but A NF 3 1/2 x 15 would be a great choice. The NF would last you a life time.
The whole set up would wiegh about 9 lb with loaded mag.
Yeah, a 300 WSM would kick a little on the bench but there are ways to get around that and you would feel little to nothing shooting game in the field.
180 AB or TSX or MRX, MV-3000 fps
165 TSX, MV - 3100+ fps
This would be a good single elk rifle for hauling around or setting up.