Originally Posted by
Palebushman
Many thanks for your input
bash bros much appreciated.
Just so I don't add too many shims, does your figure of .8mm INCLUDE
the .3 STEP that is built into the button head, like the photo?

This is the bit I can't get my head around.('scuse the pun)

.
Nope, there should be three separate shims under the button. Two alum .3mm and a .2mm copper shim... part #s 03005 and 03003 respectively.