Hi restnight,
I would need to know the details about the materials and components inside the mattress to make any meaningful comments about it (including the thickness of the layers) but based on the limited information in your description I would guess that the issue may be in the “soft memory foam” or as you mentioned the layers could be shifting. The “lump” on one side could be from a foam encasement that was the wrong height. It’s difficult to know what may be happening without being able to see the mattress or without more specific information about the materials inside it. The materials that do include the “quality” specs are all good quality materials (1.95 and 2.5 lb polyfoam) but there is also a lot of missing information about the mattress.
Yes … it would be “about” a 70% synthetic and 30% natural blend.
The “value” of a mattress purchase depends on how well it matches your specific needs and preferences in terms of PPP, the quality of the materials, on the other parts of your personal value equation that are most important to you, and on how it compares to other mattresses you are considering and the other finalists that you are comparing it to. While it is probably more costly than other Talalay latex mattresses that use the same or similar materials … some of the other parts of your personal value equation that are important to you (including how well it matches your needs and preferences in terms of PPP) may justify the cost. A mattress is much more than just a “commodity” where the price per inch of foam or the cost per pound of the fabrics or fibers can be used to assess the “value” of a mattress purchase although of course a higher price doesn’t always indicate a better quality mattress or a mattress that is more suitable for you.
Unfortunately … there are too many unknowns, variables, and personal preferences involved for anyone to be able to suggest a specific mattress that would be suitable for someone else that can be more accurate than your own personal testing or experience (see mattress firmness/comfort levels in post #2 here).
Asking about the specific cause of a particular “symptom” on a mattress would be something like phoning a doctor and asking about the cause of a particular back symptom you are experiencing when they couldn’t see you in person and knew little about you or your specific circumstances (or in this case the mattress you are sleeping on).
Post #2 here and the posts it links to has much more information about some of the more common symptoms that people may experience on a mattress that can help you do the detective work that may be necessary to identify the underlying issue but in some cases … especially when you are dealing with health issues that may put you outside of the “averages” for other people … it can involve some detective work and some good reference points. If I had to guess … I would say that it’s almost certainly an alignment issue and that the mattress may be too soft and that either the comfort layers are either too thick/soft for you or the support layers are too soft (which isn’t likely with the firm zoned innerspring you have).
A forum search on fibromyalgia (you can just click this) will also bring up more posts and discussions with others that are dealing with some of the same issues that may also be helpful although a mattress that works well for one person with fibromyalgia may not work as well for someone else. Again in very general terms you would likely need a design that provided very good pressure relief but where the comfort layers aren’t so thick and soft that you sink down too far into the mattress. If your hip joint is out of its neutral alignment and overextended then it could aggravate the sciatica.
I wish I could be more specific but I can only help with “how” to choose rather than “what” to choose. There isn’t any formula that can be used to choose a mattress for a specific person and it’s as much an art as a science so it’s not really possible for someone else to know which mattress you will do best with out of all the thousands that are available in the market and your own testing and/or experience is really the only reliable way to know which mattress is best for you in terms of PPP.
Phoenix