Hi, I am rebuilding a Mandolina hand crank organette.  I can see
that the flap valve leather, inside and out, was replaced at one time.
The flaps are 2 inches square, tacked on the four corners, with a hole
in the center for air movement.  The leather appears to be thin pouch
valve type leather and measures .015 inch.

Question: would the original leather flaps have been this thin?  These
are pretty stretched out.  Would something a little thicker be better?

Thanks, Guy Forstrom