They don't adhere all that great and it's a real pain to remove them from their backing without the sticky stuff peeling off along with the paper, but I am still pretty excited to have found these:
http://www.amazon.com/gp/aw/d/B002KBV2B8I've got big hands and a claw grip, and have never really been able to find a mouse that's a perfect fit. Only the G9x with a custom "jumbo" shell came close. With these, I can place the "blisters" such that mice I found unwieldy and/or uncomfortable are entirely satisfactory, and they even fix the couple kinks in my G9x's. They're particularly lovely placed on the buttons.
Not a perfect product, but very useful for anyone having trouble finding a mouse with all the right features except a fitting grip.