I use the stopper to record the TDC mark on both the clockwise and counterclockwise rotation. I did my best to make the numbers even in both directions then set that number as 0. Then I actually removed the checker to see where the highest point of the number one lobe was. I also did it with the checker in place and set that at 0. Then I rotated clockwise till I hit .050, recorded the number, then rotated it again clockwise till I hit .050" again and recorded the number. I added them together and divided by 2 to get the final ICL number.