Broken Scope Mount Screws

Here is a little background. Picked up a Remington Varmint in 220 swift that had 1" Burris scope rings/bases. Not sure what the previous owner used to mount the rings and bases, but red loctite is a very strong possibility. Front base came out, but front screw broke inside the action. Rear base was really a pain and no amount the WD40, brake cleaner or heat would loosen the screws. Went with an easy out and couldn't get the drill bit to bite into the screws. Drilling out the front screw of the rear base worked fine but not the rear screw. Rear base eventually came off, but only because the rear screw snapped and remains in the receiver below the action surface

Rifle is off to a smith to see if they can extract the two screws. The threads on the two that I was able to remove the screws from seem fine, but can't speak for the other two. Since the screws are still in there, assumption is that they still are but not sure if that will be the case after they are removed.

Is offsetting the base and drill and taping new holes in the action a possibility? There is enough real estate on the action to move them but not sure if I need to plug/seal the original holes. These holes are to the rear of the bolt face, so assume no pressure/gas issues.

Not sure what screw sizes Remington uses in their action, but assume they are 6-48. Another option may be to step up to 8-40s but that would require opening up and rethreading the Talley scopemounts.

Opening up the holes in the action and bases to 8-40 is what makes the most sense.