Sorry mate, sounds like you got a dog. The vintage style tailpiece setup with a mid 70's neck angle sounds like it may be unworkable.
Add to that, it sounds like there are issues with the straightness of the neck/frets.
That scarf joint = low end/budget build quality I'm afraid, although it's a strong joint and there's nothing wrong with it when it's used close to the headstock IMO.
One of the LPs that I had was tonally destroyed by a tech cranking the tailpiece all the way down onto the top. It was night and day difference and it sucked.
Many luthiers (if pushed) will tell you that 10-46 is the absolute minimum string size you can use on a Gibson scale guitar.
Add to that, it sounds like there are issues with the straightness of the neck/frets.
That scarf joint = low end/budget build quality I'm afraid, although it's a strong joint and there's nothing wrong with it when it's used close to the headstock IMO.
One of the LPs that I had was tonally destroyed by a tech cranking the tailpiece all the way down onto the top. It was night and day difference and it sucked.
Many luthiers (if pushed) will tell you that 10-46 is the absolute minimum string size you can use on a Gibson scale guitar.