Courtesy of a tweet yesterday from Scoring Sessions - the site which has provided coverage of more than a few of Trevor's score recording sessions (and I have a link to their archive in the "Neato Stuff" section on the front page) - it appears Trevor has at least reached the spotting stage in this project.
Hopefully this means they'll post photos from the session at some point in the future, although it's been a while since we've been allowed to see the Maestro at work in this capacity.