Benbow, insightful posts. Where I disagree is with your assessment of the bow hand fulcrum and virtual bottom limb length.
The static fulcrum (the balance point before we begin the draw) is the center of the bow.
Then during the draw, the dynamic fulcrum under the bow hand follows equilibrium, which is dictated by bow design, tiller, and our holds on bow and string. In my bows, the dynamic fulcrum stays between bow center and string fulcrum. It would only be below center if the bottom limb was much too strong and I was greatly heeling the grip. Not my idea of a balanced draw.
So mine moves slightly 'up' from bow center toward the string hand fulcrum, which are less than an inch apart, making the virtual bottom limb length longer at full draw than it was, not shorter.
How far it(dynamic fulcrum) slides in any particular setup, and whether or how much it changes the lengths of the virtual limbs/levers, depends on many factors, some already mentioned in this thread.
You can situate or reveal the position of the fulcrum, and virtual limb lengths, by placing something under the handle so that it creates a single point of contact, and move it around until the bow balances on it as it's drawn. If not where you want it, adjust limb strength. Of course, while pulling the string how it will be pulled when shot.