Hi Mikec

Since a 1950 M70 is factory drilled, my suggestion (from an early 1950’s Shooter’s Bible) would be a Redfield JR one-piece base (get the period correct one, not the newer “streamlined” base) and Redfield 7/8″ solid rings (the ones split at the top only).  These have the nice period feature that the front ring has two screws, while the rear ring is narrower with only one screw.  If original finish, the windage adjustment screws on the base and tension screws on the rings are color case, not blued.

Period Redfield fully split rings in 7/8″ are difficult to come by, expensive, and not necessary since you can remove the ocular bell of the Lyman Alaskan to slide the ring(s) on.

Cheers