Guys since I have everything in front of me I looked into this just now.
What I have in stock with the Falcon spinners fits the Pletty Advance shaft perfectly without modification.
I think Falcon may have opened up the tolerance a tad.
Here are some pictures to back up my claim.
Also the Falcon backplates are made with a 10mm hole. They add an 8mm insert that can easily be punched out.
Thanks, Mike