Interesting thoughts. Yes, I did read it all. My question would be, how to you get your spine to create the pattern you show in the last diagram. Is it actually doing that? Or are you utilizing other muscles/soft tissue to get the effect?
2D stick man is inherently more gifted at achieving that pattern of extension than I am, since he does not have to worry about two sides of his body or which way it is angled, and also because I can correct his position to taste.
It involved consideration of how the shoulder area and hips can extend into their respective limbs and spine, and how the spine can extend along various degrees of freedom, that I could barely manage to get approximately right when someone was guiding me into it in person over a couple of weeks. But it at least felt like there was a pattern of extension through the entire body in that shape, though it does not feel or immediately look like it extends through the way one would imagine it to go through based on the bad stick figure.