Hi Jae,
Unfortunately … only you can feel what you feel on a mattress so the only way to choose a mattress that is the best match for you is your own personal testing or experience. While I’m always happy to help with “how” to choose … it’s really not possible to give that kind of specific advice based on mattress specs or “theory at a distance”.
[quote]the Lumina Cadence Luxury Firm has a firm base, but the foam topper got quite a bit softer.
To keep a mattress as firm as it s in the showroom (keeping in mind I don’t want horrible pressure on pressure points), is it better to skip pillow toppers altogether? And if so, is foam/latex a totally bad choice?[/quote]
This is the part where it’s possible to be a little more specific. A mattress or sleeping system will soften and break down from the top down and all foam materials (or toppers) will get softer over time to different degrees and there is no way to avoid this. This will happen much more slowly with higher quality and more durable materials though than it will with lower quality materials which is why in addition to making sure you do some careful and objective testing for PPP … it’s just as important to make sure you know the quality/durability of the materials inside any mattress you choose … especially in the upper layers.
The issue is not so much with pillowtops themselves but with the quality of the materials inside the pillowtop. Higher quality and more durable materials will always stay closer to their original properties over a longer period of time than lower quality materials. The general guidelines I would use are in post #4 here. If you can find out the information you need about what’s inside any mattress you are considering and post it on the forum then I’d also be happy to make some comments about the quality of the materials or make some general comments about the mattress.
There is also more about the factors that can affect the durability and useful life of a mattress relative to each person in post #4 here. I would also keep in mind that “just enough” thickness and softness in the comfort layers to relieve pressure points in your most pressure prone position (usually side sleeping) is usually a safer and more durable choice because if you choose a mattress that is “on the edge” of being too soft for you then even a relatively small amount of foam softening can put you outside the range of support/alignment or comfort/pressure relief that is suitable for you even if the materials themselves are still nowhere near the end of their useful life and the mattress could still be fine for someone else for many years (see post #2 here). In other words choosing a mattress that isn’t “on the edge” of being too soft initially is also a big part of how long a mattress will be suitable for you to sleep on.
Phoenix