@KMC I have the same question about NDOF functionality in the ExScan Rigil application for macOS. I have opened a new thread for it (specifically for the Rigil). I believe ExStar and ExScan Rigil share the same software foundation, so a fix for one may result in useful for both apps.
Here is the Rigil-specific post: ExScan Rigil macOS support for 3DConnexion space mouse / NDOF device