Hi Realigned,
Unfortunately I don’t have any specific suggestions because the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components would be the best “match” for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) or how a mattress will “feel” to you based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing (using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
I can certainly help you to narrow down your options, help you focus on better quality/value choices that are available to you either locally or online, help you identify any lower quality materials or weak links in a mattress you may be considering, act as a fact check, answer any questions you may have along the way that I am able to help with, and help with “how” to choose but only you can decide which specific mattress is the best match for you in terms of PPP or all the other parts of your personal value equation that are most important to you.
I know that you’ve read the tutorial but two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of PPP that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability, durability, and value.
If I was in your shoes I would avoid the major brands (such as Simmons, Sealy, or Serta) or any mattress that uses lower quality or “unknown” materials in the comfort layers especially (the materials in the attachment you posted are very low quality/density and would be a significant weak link in the mattress in terms of durability). I would also avoid the chain stores that you are dealing with (see the guidelines here). No matter how it may feel in a showroom … if you purchase a mattress that uses lower quality materials that would be a weak link in the mattress then they can soften or break down much too quickly relative to the price you paid and the premature loss of the comfort and support which was the reason you purchased the mattress is isn’t covered by mattress warranties (see post #174 here).
Zoning can certainly be helpful for more challenging situations where it can be more difficult to find a suitable mattress that is a good match in terms of PPP either because of unusual body types (such as a larger differential between the waist and hips or waist and shoulders or unusual weight distribution) or other more challenging circumstances (such as a less flexible spine or greater sensitivity to alignment issues or various physiological or health issues). I think in your case it may be well worth considering.
Zoning can provide firmer areas under the heavier parts of the body that need to be “stopped” from sinking down too deeply or under the more recessed parts of the body that don’t contact the mattress as firmly (such as the small of the back or the waist) to provide better support and alignment while at the same time it can allow for thicker or softer layers under the shoulders which need to be “allowed” to sink in more deeply to provide good pressure relief. There is more about zoning in post #11 here and the posts it links to.
A body pilow can also help with alignment for side sleepers so it’s good to hear that you are using one.
I would also keep in mind that a suitable pillow that keeps your head and neck in good alignment can also make a significant difference in preventing pressure issues on the shoulders and for other upper body “symptoms” as well.
Just for reference … there are some additional posts that may be helpful to you as well. They are post #2 here which includes more detailed information about the most common symptoms that people may experience when they sleep on a mattress and the most likely (although not the only) reasons for them along with post #2 here and in post #4 here which has more information about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”.
In many cases like yours where you are having difficulty finding a suitable mattress the knowledge, experience, and guidance of a good retailer or manufacturer that you are dealing with can be one of the single most important parts of a successful mattress purchase and if you let me know your city or zip code I’d be happy to let you know about some of the better options or possibilities I’m aware of in your area.
The tutorial post also includes several links to the better online options I’m aware of as well and many of these provide some very good options after a purchase to either exchange a mattress or individual layers and components inside it or if all else fails to return the mattress for a refund.
Phoenix