Thanks,

Yeah my concern is anything I do to fill the hole will make drilling the string holes straight more difficult. Especially as I’ll be using a hand drill. I guess taking it easy without taking too much at a time is the way. I might have some small dowel in stock otherwise matchsticks it is.

Yeah my plan is drill a new hole from under the bridge into the bridge pup cavity.

If I did shape the heel of the neck to fit the front of the pocket, that would push the bridge backwards a few mm. And that might be enough to miss the existing bridge grounding wire hole.... 🤔