SUCCESS

The solution was to discard all the sage advice. I successfully created a bootable clone from the bootable thumb drive using an OWC Envoy Pro USB 3.1 Gen 2 SSD connected to a USB 3.0 port. It was slow, taking several hours for complete recovery, but it is bootable and 100% complete including a full restore from the Time Machine backup. How practical this would be to do very often is a subject of conjecture but more on that tomorrow. Right now it is past my bedtime.


If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein