Actually you didn't need a strobe. All you needed was to be in a room with fluorescent lighting. The 60 was for calibrating in countries with 60hz mains (ie USA) and the 50 was for calibrating in countries with 50hz mains (ie UK).
There's a liner pot with a standard slotted screw head, you adjust it 'til the bars stand still with a floppy loaded and the head engaged.