Yep, I had found the notes pages with the dimensions for the circled numbers. I should have mentioned them in my post....
Since the zero line is actually below any of the structure of the cab or frame, I'm guessing that point must have been on an assembly jig that the factory used. If so, it would make using a standard to measure those identified points simple...but I'm guessing. Since the frame top is at 10 inches, I can build a small wood box, who's top sits 10 inches below the top of the frame. That would give me the zero line from which to measure the other points.
