How is this done? Is it a thick piece of rubber that requires the cobbler remove a portion of the sole and install the tap sole? If this is so, then what happens to the stiching?
Or is it a thin layer very similar to the Vibram or Topy oversoles just for the toe?
They shave or cut out the top layer of the outsole. Think of it like removing a layer from a birthday cake and putting in the tap. It is flush with the sole. They don't cut so deep that they shave off the stitches (at least in mine).