I'm very familiar with the collimation of Telescope Optics, owning, and having owned many different optical designs over the past 35 years.
Just like Aligning a Optical Mirror, or Lens-Corrective Lens, I found that as one rotates the Platter, one can easily see via Dial indicator, where the high-low spots on the Platter were, and with those areas facing towards the Dial Indicator, one could make the necessary adjustments, of up, or down.
Just like with Optics, I found just a careful slight nudge of the Adjustment Screw, practically a 1/00th of a turn, to where the Screw just began to turn, was almost too groos of an adjustment.
Almost similar (but not as hard) to using a MintLP Protractor, where one goes back, and forth repeatedly, to get the adjustment perfectly set, I concluded that any imperfections were due to reasons other than errors with the adjustment, just as imprections in the Platter machining itself, errors of the Dial Caliper, or lack of getting a perfect final adjustment.
I'll state further, that I made a Paper Mat from an old LP Paper Inner Sleeve to protect the Acrylic Platter's Surface from possibly being scratched by the Dial Indicator's Metal Tip. How much deviance from being true, the makeshift Paper Mat was, I have no idea!?
Mark