Ok, so I decided to check my records tonight since I'm still rolling...
The shoulder washer (they call it a bushing) that I sourced, and no their website isn't as easy as your favorite monopoly but it's the right product and the price is right in quantities of 100...
the parent page?
And surprisingly Hammond makes the isolation kit too
So, there ya go, many options, you should be able to take it from there
Doug
N7BFS