DM - Just out of interest, how different (in terms of distance) is, say, bottom Ab from G# on a violin? I appreciate there can be a difference when free from the equal temperament of an accompanying instrument such as piano, but always assumed such details were adjusted intuitively by ear, rather than learned literally. To the best of my (hazy) recollection, I don't think I've ever seen such distinctions made on the fingering charts of wind instruments, though my experience is more with 'early' instruments than the more well-developed orchestral ones.