Thank you all for the feedback and advice. At this point, given the advice I've received here and elsewhere, I'm going to return this spinner and bite the bullet and call Tru Turn and have a chat with them about the various options. From what I've read they are very good at providing a complete solution for a very specific setup. If they can't recommend something I'll fall back to a fancy prop nut of some sort.
Thank you all again!
-Matt