You can remove the elevation slide from the Lyman, but with regular scope mounts you will not be able to reinstall the elevation slide because the rear scope mount will interfere with it. The only mounts that would allow for you to remove the scope and replace the elevation slide are side mounts, which require drilling and tapping the action. That is a beautiful rifle, don't put anymore holes in it.
I've had a pre-64 Model 70 set up like yours, and what I did was just remove the scope mounts when I wanted to shoot iron sights, then put them back on when I wanted to scope the rifle. Not a field expedient setup, but my backup system in case of scope failure is a second scope, pre-zeroed in rings.
As for scopes, the Leupold you mentioned will work just fine, though I prefer Leupold M8 3x's or 4x33's. As for bases and rings, I use steel Weaver bases and steel Burris Zee weaver rings. These allow for the bolt to clear the smallish rear objectives on those scopes.
