Hi Ellbaker,
Just as an initial suggestion … any type of material can have a wide range of layering and softness/firmness which can “fit” different body types and sleeping styles so your back issues are more likely connected to the type of layering and firmness levels in the comfort and support layers of a mattress you are trying than the materials themselves. Of course latex is fast response and memory foam is a slow response material so if you prefer a slow response material (and this is a preference issue because both materials can provide good pressure relief in a comfort layer) … then memory foam (or slow response latex if it’s available in the area) would be the way to go.
Unfortunately, Sealy doesn’t disclose the details of the memory foam they use in the Optimum series but the specs of the base layers are in post #48 here.
In the case of the Radiance … the base layer is their lower quality 1.5 lb polyfoam so any good quality memory foam mattress you are likely to encounter will likely have higher quality polyfoam in the support layers. The base layer is also on the soft side because the top 2" is only 20 ILD and is really part of the comfort layer in terms of softness.
So the challenge will be to approximate the memory foam layers which would have to be done by “feel” rather than by “spec” because the specs aren’t available. It is very difficult to match a subjective “feel” of a mattress unless you are doing side by side testing at the same time because subjective memory is not so accurate after a few hours of testing mattresses. Because of this … it is usually more effective to try to identify and “match” a set of more objective characteristics as your “standard” along the lines of post #2 here.
This way if you are dealing with an online manufacturer you will be able to describe what you are looking for in more objective terms … along with the known specs of the Radiance … and the odds are much greater that you will “match” your needs and preferences rather than another mattress (and perhaps improve on the Radiance as well at least in terms of the quality of the base foam).
A few of the better online memory foam manufactures are listed in post #12 here and several of these are members of the site which means I think highly of them. A conversation with some of these may help you identify some good choices that would meet your “target” as well as the Radiance.
It seems to me that you also prefer slow recovery materials so I would consider testing some of the Gel foam models made by Jamison instead of the latex models. These may be closer to what you are looking for.
There are also some other local options listed in the Huntsville area in post #2 here and some phone calls could also help you identify some better quality/value memory foam / gel foam mattresses that may also be worth testing. Restonic for example also makes some gel memory foam mattresses that may have better local value.
If nothing shows up locally … then some conversations with online manufacturers that include the best information you can provide about what you liked and didn’t like about various memory foam mattresses will help them “match” you to the best possible choice in the models they have available.
There are many cooling features in a mattress that work together to affect sleeping temperature. One of these of course is the outlast (phase change materials) used in the Optimum but there are many others and some of them are more effective than phase change technology. These include the types of foam used in the top of the mattress along with the ticking (cover) and quilting layers, the mattress protector, sheets and bedding all of which work together to regulate sleeping temperature. There’s more about cooling down a memory foam mattress in post #6 here and more about the three main types of cooling technologies used for temperature control in post #4 here. These will help you choose combinations that will help any mattress sleep cooler.
Phoenix