The way I set up a new saddle is by starting at the beginning of the process on a trainer.

Adjust saddle height so there is about a 25 degree bend in my leg at extension during the pedal stroke.

Adjust fore and aft position of the saddle by using a plumb bob to position the point just below the kneecap directly over the pedal spindle when the crank arms are in the 3/9 o'clock position.

Adjust to the reach I want by using the correct stem length.

This process will get to a good starting place for micro adjustments. It is also the process used by a lot of bike fitters. Sometimes, if things are not feeling quite right on one of my bikes, I'll go through this process just to make sure every thing is close to the way I set it up originally.