How do yall set saddle fore aft?

like what's your logic or what feel do you look for when riding the bike ?

Should my knees be right over the pedal spindle like on top of the cranks or should I be sitting behind the crank pushing it in front of me?

I find the Kops thing confusing in that the plumb line dropped from the knee is dropped from different points of the knee depending on which source your reading from i.e some say front of knee , others down through center of the joint , others the bony protrusion at front , so depending on what I go by it could vary by up to 3-4 centimeters.

The balance method doesn't work for me either , I can support myself with hands off the bar leaning forward no matter where i put the saddle.