Hi ImTired.
Thank you for your post. I’ll do my best to provide some good information to your questions.
The Unison mattress is all latex. The top two layers are each 2" of latex, and the 5 lbs. refers to the density of the latex.
You are certainly looking at a good quality/value mattress and as you know latex is also a very durable material so there are no lower quality materials or weak links that would compromise the durability or useful life of the mattress. Memory Foam Comfort and Dormio are also members of this site which means that i believe that they compete well with the best in the industry in terms of their quality, value, service, knowledge, and transparency.
These are both one-sided mattresses.
All of these questions refer to similar concepts in selecting a mattress, so I’ve grouped them together.
While I can certainly help with “how” to choose … It’s not possible to make specific suggestions or recommendations for either a mattress, manufacturers/retailers, or combinations of materials or components because the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort”, firmness, or PPP (Posture and alignment, Pressure relief, and your own Personal preferences) or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see post #2 here).
I’m not sure what you’ve read since you found the site but just in case you haven’t read it yet … the first place to start your research is the mattress shopping tutorial here which includes all the basic information, steps, and guidelines that can help you make the best possible choice.
Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort” and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on all the parts of your personal value equation that are most important to you.
Assuming that the materials in a mattress you are considering are durable enough for your body type and meet the quality/durability guidelines here relative to your weight range … the choice between different types and combinations of materials and components or different types of mattresses are more of a preference and a budget choice than a “better/worse” choice (see this article).
I would also avoid making a “rush” decision without doing “enough” initial research and testing to make a suitable choice in terms of suitability, durability, and your own personal preferences because the risk of making a choice that will leave you in a worse position than you are now would be much too high … particularly if you make a poor choice and don’t have any good options available to return or exchange the mattress for another one that would be a more suitable choice.
When you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc.) and the options they have available that may be the best “match” for you based on the information you provide them.
It is important that the foundation be strong enough to support the considerable weight of a latex mattress and not deflect as to cause undue sagging in the mattress. A more detailed explanation of foundations and their importance is found here.
Good luck!
Phoenix