Hi Al Shawa,
Welcome to the Mattress Forum! 
You can see my comments about so-called “review” sites (which are mostly really just “revenue” sites) and sites that amalgamate mattress reviews from all around the internet, and sites that know little about mattresses or mattress materials in post #11 here and in posts #4 and #6 here.
While other people’s comments about the knowledge and service of a particular business can certainly be very helpful … I would always keep in mind that you are the only one that can feel what you feel on a mattress and I would be cautious about using anyone else’s suggestions, experiences or reviews on a specific mattress (either positive or negative) or review sites in general as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you. In many if not most cases they can be more misleading than helpful because a mattress that would be a perfect choice for one person or even a larger group of people in terms of comfort, firmness, and PPP (Posture and alignment, Pressure relief, and your own Personal preferences) may be completely unsuitable for someone else to sleep on (even if they are in a similar weight range). In other words … reviews or other people’s experiences in general won’t tell you much if anything about the suitability, quality, durability, or “value” of a mattress for any particular person (see post #13 here).
I appreciate your kind words. I don’t pay to promote this site through online search engine optimization, and if you search for “mattress reviews” (this site has never been nor will be a “review” site), we wouldn’t show up as #1 in that particular search ranking. Many “review” sites actually pay to promote their own sites using our site name as part of their key words!
That sounds like a strong configuration if you’re building your own murphy bed and a 3" gap should meet most memory foam requirements for support.
Similar products have been mentioned before on the forum, and it performs a function like a coir bed rug. I don’t have any specific feedback on this specific product, but it is designed to promote airflow.
The most accurate answer is that it can…and it can’t. 
The thickness of a mattress is just a side effect of the design and by itself isn’t particularly meaningful because whether a thicker or thinner mattress would be better or worse for any particular person will depend on the specifics of the materials (type, firmness, etc.) and on all the other layers in the mattress. Thickness is only one of many specs that are used to make different mattresses that perform and feel differently and that makes a mattress suitable for one person and not another. There is more about the effect of thickness in post #14 here. Regardless of how thick or thin a mattress may be … the most important part of the “value” of a mattress is how suitable it is “as a whole” for your particular body type, sleeping positions, and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) regardless of how thick it may be. The overall thickness of a mattress that is either “needed” or “preferred” would depend on the combinations of the layers and components that are needed to achieve the design goal of the mattress and provide the PPP (Pressure relief, Posture and alignment, and Personal preferences) that can best match each person and their unique body type, sleeping positions, and preferences.
Both the Presto and Cumulus memory foam mattresses use high quality materials that would be appropriate in durability for your BMI.
I’m not familiar with the specifications of this mattress, but I do think highly of Sleep Boutique owner Colin and he would be able to provide a more detailed comparison if you phoned them directly.
The Leesa wouldn’t be considered “very similar” to the Novosbed line, except for the fact that it has some memory foam and is an all-foam mattress. Novosbed uses higher density/durable memory foams and offers three different comfort configurations as compared to the Leesa. You can read more about the specifications of the Leesa and the Novosbed line in the Simplified Choice Thread here that may assist you in outlining the differences.
Overall, the best advice I can provide is to learn more about evaluating mattresses, and to that end 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.
In its simplest form … choosing the “best possible” mattress for any particular person really comes down to FIRST finding a few knowledgeable and transparent retailers and/or manufacturers (either locally or online) that sell the types of mattresses that you are most interested in that are in a budget range you are comfortable with and that you have confirmed will provide you with the all the information you need about the materials and components inside the mattresses they sell so you will be able to make informed choices and meaningful comparisons between mattresses and then …
-
Careful testing (hopefully using the testing guidelines in the tutorial) to make sure that a mattress is a good match for you in terms of “comfort”, firmness, and PPP … and/or that you are comfortable with the options you have available to return, exchange, or “fine tune” the mattress and any costs involved if you can’t test a mattress in person or aren’t confident that your mattress is a suitable choice.
-
Checking to make sure that there are no lower quality materials or weak links in a mattress you are considering relative to your weight/BMI range that could compromise the durability and useful life of the mattress.
-
Comparing your finalists for “value” based on #1 and #2 and all the other parts of your personal value equation that are most important to you.
You’ve already found three site members of whom I think highly, and if you’re considering any of them I would recommend a phone conversation to acquire more detailed information and advice about which of their products they might recommend. As you are in Vancouver, subject to first confirming that any retailer or manufacturer on the list that you wish to visit is completely transparent (see this article) and to making sure that any mattress you are considering meets the quality/value guidelines here … some other possibilities I’m aware of in and around Vancouver, BC are listed in post #2 here. There is also a list of some online mattress sources for Canadians in post #21 here.
I hope that information is helpful for you.
Phoenix