I'll go against the grain here and suggest you go ahead and have the rear bridge drilled and tapped with the one hole it takes to mount a one piece Redfield style base. Much easier to find rings for it later.
However, another alternative is to find a Weaver/Warne style solid base and have it drilled and countersunk to match your screw holes and mount it that way. Then use good Warne rings.

Bob

Never underestimate your ability to overestimate your ability.