I skimmed though the Voyager document and it seems to have very good coverage of overall telecommunications system.
For the topic of the periodic calibration the following is all I could spot
>> Four 7-hour and two 0.5-hour attitude control calibration maneuvers are performed per spacecraft every year, each requiring 70-m station downlink coverage to ensure uninterrupted downlink telemetry.
While this is interesting in itself, it merely states the schedule but doesn't satisfy my curiosity about the exact mechanism used to do the recalibration.
Thanks nevertheless. Interesting reads here.