Followup to my earlier post. I neglected to mention that I have a suspension seatpost. It compresses a good inch or so when I place my not insubstantial mass upon it. That plus additional compression when I move as I pedal probably accounts for the difference between calculation and perception. As my seat gets more conditioned and my mass decreases I may switch to a fixed seatpost.

The calculations do put calculated crank length right in the normal ball park. Good intuition, Claude.
Regards,
Raymond