The dial indicator base may be mounted on the disc, so that the stylus of the 'clock' (DTI) is in contact with the end of the stub axle and truly aligned with the stub axle center line. Grasp the disc at 12 and 6 o'clock and pull the assembly towards you - zero the clock -and push away. Note the reading and adjust as required.
Zero end float, or more correctly no preload, is the desired condition to minimize pad knock back. Use the above method until you adjust the end float out. Please note, there should be no need to use a wrench after the initial bedding sequence.
Having said all of that, with a modicom of experience it is possible to set the bearing by finger tightening the adjuster nut as the hub is rotated. It certainly won't be possible to damage the bearings by hand tightening! Oh, and before someone says it - the adjuster nut should be free to rotate on it's thread.
Steve B