I wouldn't use Saddle setback to compensate for frame size. The saddle set back should be used to correctly alien our power stroke with the crankset. To compensate for frame size swap out the handlebar stem, with a different length unit.
Once you attain the correct saddle position the weight distribution is what it is and varies with the frames geometry, handlebar and stem. On my comfort bike a lot of my weight is on the seat, enabling me to climb steep hills without standing on the pedals. I'm guessing a 40/60% split vs perhaps a 45/55% for most bikes.
I used KOPS as a baseline for my saddle position and it worked perfectly. No more knee pain. KOPS may not be perfect for everyone but it is as good a starting point as any other method IMO. Weight distribution doesn't enter into it.
Last edited by xroadcharlie; 06-04-21 at 12:40 PM.