Hi kymist,
When you are trying to “fine tune” a mattress so that it’s a better match for you in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) I tend to take a more “symptomatic” approach which is generally more effective than trying to guess whether any part of your body is sinking in too far or not enough or how much pressure or support you may have under any part of your body (such as the small of your back) which would generally require more specialized testing equipment.
There is more about the most common symptoms that people may experience when they sleep on a mattress and the most common (although not the only) reasons for them in post #2 here.
There is also more 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 in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”.
These posts are the “tools” that can help with the analysis, trial and error, and detective work that may be necessary to help you learn your body’s language and “translate” what your body is trying to tell you so you can make the types of layering changes that have the best chance of reducing or eliminating any “symptoms” you are experiencing.
It’s very unlikely that a 3" soft top layer wouldn’t be “filling in” the gap in the small of your back and you won’t be able to measure the pressure under the small of your back to know how well it’s being supported (although you can slide your hand underneath to make sure that there is good contact between the small of your back and the mattress) so I would tend to go by any symptoms you are experiencing rather than on more technical or “theoretical” assessments or what a mattress “feels like” which are all more unreliable than the actual symptoms you experience.
The most common cause for hip pain is a pressure issue but hip pain can also come from a mattress that is too soft where your hips are sinking down too far and are outside of their neutral range of motion. You will generally feel pressure issues fairly quickly and if the symptoms you are experiencing take more time (after several hours of sleeping or when you wake up in the morning) and go away when after you get up and have moved or stretched a little then they are most often related to alignment rather than pressure issues.
Did you experience any lower back pain on this combination?
It would be worth exchanging the firm and medium layers so that the firm layer is in the middle to help you firm up the support of the mattress and prevent you from sinking down as far. When you have slept on this configuration for a few days (long enough so that your experience shows a “pattern” and isn’t just an anomaly) then the changes in your symptoms on this layering compared to what you experienced on your original layering will help tell you whether you are going in the right direction and help “point to” any additional changes that may be necessary.
The most important priority is always good alignment and once you are sleeping without any alignment “symptoms” then you can focus more on any pressure relief issues you may also be experiencing.
This may be an indication that you are making changes in the wrong direction and softening up the support instead of firming it up. Lower back pain is most often a “symptom” of a mattress that is too soft and is allowing your hips/pelvis to sink down too far.
I would need more specific descriptions of each of the combinations you tried because your descriptions of the layering combinations and the specific symptoms you experienced on each of them aren’t specific enough or descriptive enough for me to know what may be happening. To be able to guess what may be happening I would suggest making small incremental changes and I would need the specifics of each layering combination and a description of how your specific symptoms changed in comparison with the combination before it to be able to make any meaningful comments or guesses about any other combinations that may be worth trying. The “changes” in your specific symptoms with each combination are the most important part of the process of “learning” to translate what your body is trying to tell you.
At this point I don’t have enough clarity about the causes of your “symptoms” to be able to make any meaningful suggestions that may be worth trying.
It would be helpful if you could describe your experience on the S/M/F more “symptomatically” and then it may be worth trying the S/F/M to see how your symptoms and sleeping experience changes in comparison so I have a better idea of the effect of firming up the support of your mattress.
I would also talk with Spindle so that they can provide you with any suggestions they may have as well since these types of issues are much more effective to discuss on a phone call than the more “linear” and less “nuanced” type of descriptions that are possible with written communications.
Overall … you have tried too many different combinations and I don’t have enough information about the specifics of each of them or how your experience and “symptoms” changed with each of them compared to the one before it to have a clear idea of what may be happening.
Phoenix