I have tried a "clean start" following these instructions by Dhauzimmer found at FrenchToast's web site:
Still no joy but I do feel like I am getting familiar with what is involved with this whole driver installation process.
I can't believe that I am the first person trying to get these older/unsigned drivers to work under a newer windows OS.
You can rest assured that when I finally do have the solution it will documented here for the benefit of others.