I have just completed my new rocker jig. (thanks Dr Funk for the inspiration)
It will do to up to 3 meters when the final brace is attached and is an ideal way to transfer the rocker from a blank cut on the cnc machine without printing paper templates.
Good stuff. Perhaps if you use medium/soft rubber washers between the flat-bar and the brackets you can eliminate the flat spots completely? Where did you find the slotted hinges?