If you dont think saddle setback has no effect you are wrong....I will use myself as an example. I ride a 53.5 virtual top tube with a 135mm stem....normally I would be a 120mm stem, but I ride with a saddle setback of 25mm because I have a 32.75" inseam but I have short femurs relative to tib/fib.

That makes my position high and short since the relative distance of hip to crank arm spindle will not change...just the angle between my hips and the spindle..(lower and back or higher and forward)

Sitting about 25mm more forward than a person with the same build but longer femurs places my upper body that much farther forward and thats why I have a super long stem. Alternatively I could ride a 55cm with a 120mm stem. My measurements ideally put me at 66cm not 67cm but the saddle setback forces me just a little farther forward