I was helping Dave Heithaus, a new measurer, and he showed me a trick I’d not seen before. I have always peered downward at the calibration mark to see when my wheel was right on it. Dave did it as you see below:
He flipped down his kickstand and put it right on the mark. He does this when calibrating.
With all the years I’ve spent at measuring this was a trick I’d never seen before.