I'm putting rubber (neoprene) washers on both sides...I'll need to add room for that too. Are you doing that too?
I also got some black surgical tubing to make the tiny little bands for the screws.
I don't have to have a front plate for AZ, but I haven't tried the 40s yet to see if they'll work with my washers.
Mav if ya end up having to buy a boatload, I'll buy some from you. I'll probably need them.