How can I create proxy videos from Ursa Mini CinemaDNG sequences?
Apparently I was just missing the setting.  While Optimize Media has been changed in such a way it will not work, there is now a Media Management function that will handle this perfectly.  It is available under the File menu I believe it was.

Media Management allows moving, copying and transcoding of all footage in the project, all footage in a timeline or particular clips.  You can also choose to work on only the footage in the project that is actually used (useful for discarding unused clips after final editing is done).  You also have the option to relink or not to the newly created files.

Scaling it to another resolution is also an option.

In my case, I through all new clips that needed to be transcoded in a timeline, selected to export all clips from that timeline and setup the output settings and ran the transcode.  It pushed through 2.5 TB of footage in about 4-5 hours and produced 130GB or so of proxies.