I have not heard anything new on this problem, and I don't know if Tiggy ever sent Brian his settings.
Still running 8.5 here and my problem with overlays is still present but different from the OP. My problem is overlay #1 "remembers" earlier settings. I use it to show my present location. When I first bring up WD the overlay will show all my previous locations on the image. I just go to the overlay tab, select #1, and when the correct text is showing on the preview I hit save, then go back to setting #0. The first update of the preview will revert back to showing all the extra text, but the second update it will show normal. I then hit save settings and minimize the window.