Hi PaulB,
There are a few other all latex options in your price range on the list that you haven’t mentioned as well which are Brooklyn Bedding’s Total Latex Mattress and Rocky Mountain MattressMy Green Mattress collection and
Three of these have 6" base layers and a top layer on top, SleepEz has the 3x3" layers, and My Green Mattress is two sided. All of these have different designs and features and abilities to customize. All of these are well worth talking to and will give you a good perspective of the benefits of different designs.
I’m personally not convinced of the real-life benefits of a 5 zone layer which has little differential in the zones … especially with latex which has the ability to adapt to different body types and sleeping positions very well because of its natural support factor (the ability to get firmer faster with deeper compression than other materials). It can also create issues for a couple who have different body sizes and fit the zones differently and it can also restrict the choice of latex in the layer that uses the zones. A 2 or 3 zone can be beneficial in some cases but once you get more than this and where the difference between the zones is often less than the natural variation in the latex in the first place then its benefit is questionable IMO. As long as the zones are not detrimental though it probably wouldn’t do any harm. Zones that are more customized and have a larger differential have more possibilities to benefit certain people.
There is more information in the mattresses section of the site about the theory behind layer thicknesses, ILD’s, and different types of designs and construction as they relate to different body types, sleeping positions, and preferences but these are generic and meant to give you some insights into the many variables involved. Each manufacturer knows more than anyone else about all the materials and components in their own mattresses and how they interact with each other and with different people (based on their experience and the averages of their own customer base) and any specific layering choices should always be part of a more detailed conversation with each manufacturer who knows their specific mattresses and the options they have available best of all. Because of sometimes small differences in the materials, design, and components they offer … each of them may suggest something different with their own design with the common goal of providing you with the PPP (Pressure relief, Posture and alignment, and Personal preferences) that is best for you. There are also many different types of layering that can work for the same person so all of them may be the best option for the specific design they offer.
Your own local testing along with more detailed conversations with each manufacturer is always the best way to choose the layering options that may be best for you. They may also have different options in terms of re-arranging or exchanging layers or mattresses as well so make sure you take this into account in deciding which one is the best match for your “personal value equation”.
Phoenix