You probably have the treadle-on website listed as a reference for people interested in "refurbishing" their own machine, but in case you don't it is http://www.treadleon.net
You could direct people to that website as they discuss much more than just the treadle machines.
FWIW, I used to be a member of that group when it was just a list-serve mailing list, but I had to give it up as I could not keep up with the massive volume of e-mails that I received. They gave me information on how to use my treadle, as well as how to convert an older electric 3/4 singer to a hand-crank. (which works really wonderfully for paper piecing). They also have information on how to restore the older electric models, how to date the machines, where to find the parts to fix them, and how to get the manuals for the machines, including the repair manuals.