Hi Bob,
Thank you for all the trouble you went to in your explanation. I must admit, I never realised the intricacies involved, and although I worked with a very good sax player for many years, it never occurred to me to ask him.
Without needing a further explanation, I guess the same goes for brass instruments such as trumpets & troms also.

Thank you again Bob - every day I live & learn,


Cheers,
Keith