I cut away some of the material I suspected was causing the noise and it is better but still not "right". It's good enough for now, though. One sound per rotation has me scratching my head as the rotor assembly prides itself on being symmetrical. The next time I pull it apart I will mark the arbor on the spot where the noise occurs and take a look with the calipers.
Next up... separating roller carriage from the yoke and disassembling both.