Johnnieharp said: "Another issue is, even if the audience could / can tell the difference between the sounds coming from different combs or cover plates, is the difference significant enough to affect their opinion of the music."
I thought I made it clear this is NOT a test about audience opinion - that's already been done, as noted in my post. This is about what the Player and Close Listener hears.
Coverplate testing is another thing altogether, and we can't do that at the
same time. We need exactly the same covers and reedplates to go on each
different comb as it is introduced.