Set a Cap Iron. What did Stanley say?
Stanley's guidance is as vague as many sources but it's also highly accurate!
Just move it close when needed. How close? Well an 1/8th of an inch is pointless, don't expect it to do anything from there.
Simply start at 1.5mm and go from there. Use your eyes as a guide, there is no magic way to dial in the settings. 0.75mm and less as needed.
With practice you set them as required for your Jack, Try and Smoothing planes.