I managed to finally address the shoulder thing compared to before. Other things are mostly similar, except the pump/reachback is worse. I can't focus on too much at a time.
So I tried to rotate my shoulders around my spine, rather than reaching back with my right arm while pointing my left shoulder at the target. My shoulder doesn't bunch up this way, and I felt no arm use at all in my throw (compared to before). Normally I would swing my shoulder, and feel some muscles in my upper back by my right shoulder blade...again I have no bio knowledge...but today it just felt like it was legs and core. Obviously there are issues that I will mention below.
https://vimeo.com/178554285
Obviously the disc pump/reachback is still terrible and even worse. It screws up everything next. Especially weight shift is still late, my rear toes are still on the ground as I go heel-down. But is the stride length better? I tried to show the Hershyzer type plant (left) compared to the older long stride (right).
Then because I am letting my body rotate to pull my arm, I am not pulling the disc forward with my elbow, so it is not bunching up the same (left vs. right). The disc is still a little high but I think that is because I reach back a little high? My shoulder is not bunched up like in the right image, although my head is not in the right place.
Finally in the right pec position, the disc is actually on plane and my elbow is much farther forward. My head is not dynamically balanced on my body angle, so it looks close to my right shoulder, but my right shoulder isn't bunched up like in the right-hand side image.
I realize my pump/reachback are badly timed, and now that I am actually using my core more correctly to power my arm (I hope!) the improper weight shift is just nulling my core load to my arm, since I'm not just blasting with my shoulder.
But, is the shoulder/right pec looking better? Is it just my head tilt that is making things look bunched up now?
For reference I had the same ejection speeds as before, but just felt like completely different muscle groups being used, at low effort. Was throwing putters ~300'.