Cam degree..

I count 5 1/2-6 threads under the rocker. I would want five less than shown. At 20 threads/inch, thats .050 /thread. Times five would be .250.
PXL_20211017_021217224.jpg PXL_20211017_021230108.jpg Screenshot_20211016-191625.png
These are the ones that I'm thinking about ordering? Again I'm not sure where they're measuring from..