Michael, the RJB series was part of the HSCC calendar.
Courtesy of the Moity/Teissedre 2-volume LM book, here's the Schulthess car at LM75:
This car also ran with a triangular section central airbox, I know I have a photo somewhere... and Jauslin's car has this airbox - There'a paddock photo of it here:
http://racingsportscars.t35.com/phot...-16-photo.html
HU50 would have been a T292. Guess what? Schulthess ran a T292 at the LM 4hours in 1973...