I'm designing a flexible circuit that is little more than a glorified ribbon cable, but nothing "off-the-shelf" will work. (So it is just a single layer of conductors on polyimide with a coverlayer, but no tooling holes or any other features). Our first prototypes came back with the conductors off-center from the board outline. I can't find anything in IPC-6013 that addresses the relationship of the circuit pattern to the board outline, but it definitely has to be tighter than a typical rigid board. Is the "pattern-to-board-outline" relationship covered anywhere else? Do I have to add some kind of note or dimension to keep the pattern "centered" in the outline?