This was the video I was hoping for George .besides the tow vehicle or team of horse's...could one man operate all the controls of would it take two men ?
Not trying to answer for George here, but I have spent some time messing about with one in a static situation, so I'll share my opinion.
I think it would best be operated by one man on board the grader itself, as two would very much be in each other's way most of the time, and might well find themselves working the controls to cross purposes. Certainly if there was more than one aboard, there would still have to be just one "captain" in command of what adjustments to make, and how and when to make them.