Hi smeagol108,
As I mentioned in an earlier reply … once you start going past about 12" or so … particularly with thicker layers of polyfoam that are “stiffer” than latex … then it’s more likely that there can be some issues with a mattress conforming to an adjustable bed although this always depends on the specifics of the mattress. Latex is much more flexible than polyfoam and will contour to an adjustable bed more effectively.
This is really a matter of personal preference and for some people it would be worse and for some it would be better. It would really depend on the type of feel that they were most comfortable with and which of the tradeoffs they would prefer. Thicker quilted covers will reduce the ability of softer latex to contour to some degree but this can be either a negative or a positive depending on the person. There are also many people who prefer sleeping on a less resilient or more relaxed sleeping surface than sleeping directly on latex or that prefer the temperature regulation effects and the feel of having wool or other more breathable materials quilted in their cover. There is more about the pros and cons of different types of quilted covers in post #12 here and the other posts it links to.
Once someone is “outside the averages” for the combination of materials, layers, and firmness levels that would work well for most people with a similar body type and sleeping style … then there are too many unknowns and variables involved and too many different causes for the same set of symptoms to make any meaningful suggestions based on “theory” or specs (either yours or a mattress) without more more specific information and reference points. Post #2 here and the posts it links to has more information that may be helpful with the detective work and trial and error that can be involved in “diagnosing” the underlying reasons behind the discomfort and symptoms you are experiencing but the most effective approach is normally to make incremental and “one step at a time” changes and then use what you learn from your experience and the changes in your symptoms with each incremental change to decide on the direction (firmer/softer and which layer(s) etc) of any further changes that may be necessary. This is similar to a process of differential diagnosis to assess and rule out possibilities one by one until you are confident that you have the solution that will work best for you (see post #2 here).
Based on your comments your original layers were 28 ILD over 32 ILD but I’m not clear on the actual symptoms you experienced on this combination.
You then changed to 24 over 28 and also tried other combination of these three layers (such as 24 over 32 and removing the top cover) but I’m also not clear on how any of your specific symptoms you experienced changed with each combination of the degree of change that you experienced. All I really know is that you are experiencing shoulder/back and upper neck pain and in some cases this may be connected to a pillow issue more than a mattress issue.
If you can describe the specific changes in your symptoms that you experienced with each combination (which symptoms became worse and which became better with each combination and if you have any information about which sleeping positions seem to make any symptoms worse or better) then I may be able to identify something in your experience that I can use to make some suggestions that may help “in theory” but with more complex issues “theory” can often be wrong and always needs to be confirmed in real life which is the only thing that really matters.
There is more about the “value” of any mattress in post #13 here but the most important part of “value” is always how well a mattress matches your specific needs and preferences regardless of the specific layering or the number of layers. Having said that there is more about the potential differences between 2 3" support layers and a single 6" support layer in post #2 here.
Again … there are really too many unknowns, variables, and individual differences and preferences involved for anyone to know with any certainty outside of “averages” or your own personal experience and the “averages” don’t seem to apply to you (possibly because of your previous back issues). The choice between Dunlop and Talalay is also a personal preference although Dunlop does have a higher compression modulus than Talalay which for some people can be more “supportive” in the same ILD as a Talalay layer. There is more about the differences between Talalay and Dunlop in post #7 here. There are also different types of support that can make a difference and firmer isn’t always more supportive. There is more about primary and secondary support and their relationship to pressure relief in post #2 here.
As you can see these types of questions can become very complex and there are many cases where the normal “rules” don’t seem to apply to some people so it’s always a more effective approach to “learn” enough from your own personal experience and the differences between each combination that you have experienced that can “point to” a combination of layers that moves in the direction of what your body and sleeping experience is telling you instead of using “theory”.
I would always prioritize alignment over pressure relief because once you have good alignment then it’s not so difficult to add some additional pressure relief to a mattress.
One other comment I can make is that in your initial post you mentioned that you suffered from chronic lower back issues but in your descriptions of the Alexis you only mentioned upper back and shoulder/neck issues so if the Alexis solved your lower back issues then this would also be quite promising and I would take this into consideration as well.
Phoenix