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Am I thinking along the right lines in equating le bon goût with grace and elegance, or am I way off beam?[/font]
.....[hopefully, with my reply this time !!]........I think your basic premise about le bon gout is absolutely correct Vox, but I would also add "appropriateness" ie knowing when to use inegales and the degree of inequailty that should be used to reinforce the mood/Affekt of the piece.
Best summary of the historical info on this and how to apply I've found is in Laukvik Historical Performance Practice on the organ [Carus] - this book is a mine of information and an excellent primer for already technically-competent players