I recently rebuilt a nice little Panasonic 12 speed, steel frame, good shape, 52 cm effective top tube, built around 1988. I have spent all my life on road bike, and I'm having some trouble getting this thing adjusted. It's a more upright, mixte frame, without the true double top tube.

It should fit, but I'm having trouble getting the no-setback seatpost to allow me to position myself far enough back to allow a plumb line to run from my knee to the pedal axle. Is this a valid measurement for this type of bike? 700 wheels, 80 mm quill, etc. Stock seat has standard rails. Nothing special. Were women built differently in 1988?