Given that beatnik is a fitting guy I'd assume that when he says that someone changes his seatpost it's to change the fit, not the color or weight or whatever.
If you keep your saddle position the same you obviously won't change your stem. But if you change your straight seatpost for one with setback to give you a different position you have to change your stem.
So you're not actually disagreeing with him, the way I see.
Exactly, if you read carefully i say "Saddle in the center of its rails", because it´s only an aproach.
But you are clever people, the correct order is this one
1st: Saddle-Bottom bracket seatback (you can measure it with a door, put the center of bb and measure your saddle nose setback) + Saddle height
2nd. Saddle nose -handlebar axis
3rd.- Saddle handlebar height (measure your saddle-floor height and your handlebar-floor height and substract)
With 2nd and 3rd point you can check the length of your perfect stem and its angle, how much you need to cut your fork or how many spacers you will need.
It´s not easy, but be patient and make little changes from the "perfect fit" if you don´t feel completely well (we are not Symmetrics )
Biomechanical spreadsheet. Sizing&Fitting.http://weightweenies.starbike.com/forum ... 8e319d185b