Originally Posted by
europa
KOPS (knee over the pedal spindle) was discredited in the nineties - this article by Keith Bontrager was published in 1998
https://www.sheldonbrown.com/kops.html
There are others.
The saddle set back is adjusted to balance you on your bike properly and thus will vary depending on bar height, how stretched out you like to be, etc.
Certainly, with a new bike, you could transfer your numbers across as a starting point, but to be honest, I think you're better off starting from scratch. It's not hard to get a basic set up and no matter how you start, it has to be fine tuned on the road anyway.
Yes, I'd agree that KOPS is not ideal for all cases - I use the "balance test" method myself. It's interesting that you mention that this is affected by bar height, which has been one of my issues. I'm a new cyclist and found it uncomfortable to have too much bar drop, so I was playing around with all sorts of fit changes. I finally got a professional fit and moved my saddle forward and up a fair bit - I thought the increased drop was going to make things worse, but it didn't.
It sounds like there isn't really an absolute value of saddle set-back then, even for an individual, and that the ideal position could be altered by the bike's geometry and usage (e.g. race or endurance etc.).