I found it useful to rock back 'n forth a little...

Geez. My measurement's way bigger than I thought. No wonder my saddle hurts after a few miles- after taking the measurements and setting the measurin' sheet on the seat, all became clear. The 'peaks' of my sit-bones are half-straddling the seat. No wonder so much of my weight ends up being carried by my soft tissues and other bits. Ugh.