Hi hima,
Welcome to the Mattress Forum! 
I’m glad that you’ve found us!
[quote]We went to Sleep Country (prior to visiting this site) and tried on a bunch of different models. We are mainly side and back sleepers. We prefer medium-firm on the firmer side. We came across the Dormeo 6711 which to us is soft enough so that there’s no pressure on the shoulders and firm enough so that we don’t sink in too much. I also like the fact that it responses faster. In some tempur-pedic models, the slow response of the mattress feels very “weird” to me.
However, when I was trying to do more research about the Dormeo 6711, there’s not much online. Even on this forum, the last update by Pheonix was around 2015. The 6711 model is also new this year (I think).
I contacted Dormeo North America to ask for the foam densities, but they haven’t gotten back to me yet. There’s no live person to talk to, only voicemail. If they call back with some information, I’ll definitely share it here.[/quote]
There is also more information about the Dormeo Octaspring mattresses in post #2 here that may be helpful but I would make sure you can confirm the thickness and density of all the layers in the mattress (see this article) before considering it.
There are a few comments about the older Octaspring 9500 in post #2 here (you may have already seen this one) that you may find interesting but I don’t know the specifics of the current line so In hope that Dormeo contacts you because it’s unlikely that Sleep Country will provide you with the information you need to make an informed choice. It’s also possible that Dormeo may not provide it either.
As for suggestions, I can certainly help with “how” to choose, but 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 mattress firmness/comfort levels in 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 … and perhaps more importantly know how and why to avoid the worst ones.
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”, firmness, 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 (including the price of course and the options you have available after a purchase if your choice doesn’t turn out as well as you hoped for).
Outside of PPP (which is the most important part of “value”), the next most important part of the value of a mattress purchase is durability which is all about how long you will sleep well on a mattress. This is the part of your research that you can’t see or “feel” and assessing the durability and useful life of a mattress depends on knowing the specifics of its construction and the type and quality of the materials inside it regardless of the name of the manufacturer on the label or how a mattress feels in a showroom or when it is relatively new so I would always make sure that you find out the information listed here so you can compare the quality of the materials and components to the durability guidelines here to make sure there are no lower quality materials or weak links in a mattress that would be a cause for concern relative to the durability and useful life of a mattress before making any purchase.
If you can find out the thickness and density of all the layers and components in the 6711 and post them on the forum I’d be happy let you know if there are any lower quality materials or weak links that would be a reason for concern.
Most people that are looking for an “organic” mattress or materials are usually concerned more with “safety” than whether the materials have an actual organic certification and they usually aren’t aware that an organic certification isn’t the same thing as a safety certification. There is more information about the three different levels of organic certifications in post #2 here and some of the benefits of an organic certification in post #3 here and there is more about the different types of organic and safety certifications such as Oeko-tex, Eco-Institut, Greenguard Gold, C2C, and CertiPUR-US in post #2 here and more about some of the differences between organic and safety certifications in post #2 here and there are also some comments in post #42 here that can help you decide whether an organic certification is important to you for environmental, social, or personal reasons or whether a “safety” certification is enough.
Latex (natural, synthetic or blended) will have a very buoyant feel and is quite resilient (returns much of the energy in rebound), and can have a very different feel from polyfoam and memory foam.
You may wish to perform a forum search on Essentia (you can just click on the link) for some of the information about “natural” memory foam claims. There are also many more affordable choices for an all-latex product, should you desire to choose that route, including many site members listed here.
Phoenix