The big question is: Is there a better/easier/ way to do it? I have thought of making a 3 or 4 spring attachment to spindle/ not the collet/ and a sanding disc , pneumatic or electric. then program it like a grinder to take very very slow pass. I am seriously considering it as soon i will have to sand something like 200 wooden instruments and it takes me a couple of days to do that to 120 grit.

Have you seen somewhere this kind of contraption? the only similar thing i have seen is someone attach an angle grinder to his mill