Moki 2.1 and Tru-Turn Spinner.
OK, right or wrong, this is what I did:
1) I reamed out the spinner backplate to 12mm -- this is needed to mount the spinner backplate against the prop washer.
2) I first reamed out the prop to 10mm -- this clears the prop over the threads. I further reamed approximately half of the props dept to 12mm on the back side -- this clears the the prop on the part of the shaft that does not have threads.
NOTE: This supports the adapter I ordered. My adapter comes with a washer reamed at 12mm with a nut that threads onto the 10mm thread and provides a threaded receptacle for the spinner bolt. The base of the nut is designed to insert inside of the interier of the washer.
Some adapters available are designed so that the nut that includes the spinner thread receptacle inserts not only inside of the washer but also inside of the prop. If you have this type you need to ream the prop to 12 mm for its entire dept.
In every case, you ream the spinner backplate to 12mm. Tru-Turn recommends you have a machinist do this -- I found it very easy to use a reamer on a drill press.