The way the base is made, I'm not sure you'd have enough room to move it very far. And the aluminum receiver is easier to drill and tap; you can put the base where you want. You gotta be careful to not wallow the hole out with the tap, keep it straight. And, don't over tighten, use Loc-Tite.
I know drilliing the gun worked well for you. Your gun looks fine.
But years ago a lifelong gunsmith taught me a to "always modify the least expensive and/or easiest replaced part. That way if you screw it up , you have have an easier time correcting the error.
A $25 Leupold base is worth a lot less than a Ruger reciever- not to mention lowering the gun's value by drilling the reciever top with extra holes.
. I am pretty sure the rear Leupold base hole can be used and another hole drilled just ahead of it for tge two rear holes. The front screw holes may be the problem as one has to work around that rotary dovetail cut. I would think at least one screw hole could be drilled and then you would at least beeven with the origional Leupold base setup as it only comes with three holes from the factory.
Either way , it seems doable .