there are some clues on the SJS description: "110mm bracket required to get a 54mm chainline on middle ring, 107mm can be used if only using a single ring in the outer position."
I think 54 mm is the old Rohloff chainline, with the threaded sprockets. The new sprockets bump it up to 57mm, as I recall. I think a 1mm increase in chainline needs a 2 mm increase in bracket, because the bracket is measured full width while the chainline is measured half-width, i.e. center to edge.
I have never actually worked with this stuff so I hope those with real experience will chip in and correct me!
