Take it to the extreme, and make that poly finish four inches thick. How does the timber, which resonates at a specific frequency (depending on species, density, moisture content, grain structure, etc), combat the thickness of the finish? How is a strings vibration effected by the resonating frequency of the parts and timber it is fixed to? Maybe you should do a test, and it doesnt need to be on a full sized guitar, just a scrap of timber. You'll have to work out how to achieve the test, im not going to give you everything. Ive proven it to myself, and others, that a thinner (or even TYPE of) finish is without a doubt, better. Do some reading on frequencies, harmonic vibrations, sympathetic vibrations, and their effect of objects and structures. There is a lot more to building guitars, than fancy timbers.
Oz, nice guitar. I see many simularities to my first guitar.
of course at 4 inches it would have an effect, but surely a thin film has a negligable effect?
Obviously I havent done tests like you have, nor am I interested enough to do them, but my common sense would suggest that of all the things on a guitar that can effect the sound, the effect of a fraction of a mm of lacquer will be negligable...