Doug Nixon writes needing brass hardness info for trumpet reeds.
Wallace Venable's reply makes sense if the metal is not going to be
pushed to the yield point.  I have found that phosphor bronze in its
hard condition works well for music box dampers and it is nicely
workable.  Your could make a test of it at little cost.  You can get 6"
by 12" sheets from McMaster-Carr.

Bill McKeown