Also not a fan of KOPS, but it's a good starting point. Thing to do is to measure where you were w/r to KOPS on the old saddle, then establish that same relationship between knee and pedal on the new saddle. There's no reason to believe that one's butt will be in the same location on two different saddles, ether for and aft or height. For height, I always measure with my leg, heel on pedal, unless it's the same saddle on different bikes, then I'll use a tape.