> https://www.youtube.com/watch?v=LQxJgw0GhJo

Replay works fine here in OWB v1.23 (also in full-window overlay mode) with:

- http://www.youtube.com/html5 enabled
- YouTube_Fullscreen_Fix.js v1.18 enabled (youtube.js *not* enabled)
- spoofing as "Firefox 25 (Windows)" or "Internet Explorer 10" or "Chrome 32 (Windows)" (or "IPhone" or "IPad", which should also work without explicitly enabling Youtube's HTML5 mode)

For the full-window overlay mode to work, you may have to use HTTP instead of HTTPS protocol, which I guess is a limitation of the YouTube_Fullscreen_Fix.js script.
I see that a month ago you reported success using this method as well.