Hi AnalogJ,
Thanks for taking the time to share your comments, feedback, and insights in such detail … I appreciate it!
Just as a suggestion … it may be worth considering a shredded latex topper which can add some additional softness and pressure relief with less risk of alignment issues because the pieces can displace to some degree under the more “pointy” parts of the body such as the shoulders but will compress more under the wider and heavier parts of the body such as the hips/pelvis. Other types of soft toppers that are relatively thin and soft can also add some additional pressure relief with less risk of alignment issues than thicker toppers. Post #2 here and the topper guidelines it links to has more about choosing a topper if that’s a direction that you think would be helpful.
Thanks again for a great post 
Phoenix