Are you going to take down the top any to make up for the thickness of the cap? Or just use whatever the sander removed?
My local not-quite-good-enough-for-vintage shop had a double cut Les Paul Junior or Special. Probably 59 or 60, but so mutilated that you couldn't tell what it started our as. It was there for years, and I decided I would finally buy it and put a mahogany cap over the mess, using my community center's nutso wood shop. It sold a couple of weeks before I went. DANG.
When I first saw that, I thought you could bind and flame top it.