ok.. i've suffered a life time of being crap at maths and physics..
and so not managed to read most of this thread..
so cant really say how relevant this is..
but in the practical world..

about 10 - 15 years ago Jimmy Page used a guitar prototype
which he demonstrated on TV [Tomorrows World..???]
..a converted les paul,
with body cavities containing electric motors, circuits, sensors,
and other technical stuff..
providing the guitar with auto tuning functionality..
it was supposed to be able to monitor and self correct fine tuning,
and also be switched immediately to pre-set alternative tunings..
This function was demoed convincingly on Tv..
providing otherwise impossible alt. tuning changes
at the flick of a switch at any time within a song performance..

anyone else remember..??

..i'm not making this up..

i guess the technology was too expensive and uneconomical to ever be developed commercially..