I made one of these a few years back using a Ruger #1 action and chambered it to .500 3 1/4". It had a 24" heavy barrel and weighed 9.5lbs. and was too light for the loadings possible in that round. If you stuck to 570s at 2150 or so, it was great. I took some 650s up to higher velocities and the recoil was getting really harsh. It sure stopped animals in their tracks, but was past my comfort level to shoot much. If I did it again(and I might) I would make it a bit heavier likely using that same heavy contour but going to 26".
I used the NECG rear sight on a Ruger rib and a large NECG bead out front. The sights were great. The whole rifle was great and I regret having parted with it. I am sure you will enjoy your rifle.
I was very surprised by the accuracy I got from this big .50. It was one of the most accurate rifles I have ever used of any caliber.
Good luck, I hope your rifles shoots as well as mine did.