Hi paperman,
Hopefully you’ve had the chance to read the tutorial post (the link is in the top right corner of the page) which has all the basic information, steps, and guidelines you will need to make the best possible choices … and know how and why to avoid the worst ones.
Post #4 here also has some of my thoughts about buying a mattress from a big box store like Costco.
Unfortunately the “specs” you listed don’t include any information about the quality of the materials in the mattress (which is fairly typical of major brands who don’t normally provide this information to their customers).
Outside of how suitable a mattress is for your specific needs and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) … a mattress is only as good as its construction and the quality of the materials inside it and without knowing this you would be making a completely blind purchase with no way of knowing anything about the quality or durability of the mattress you are buying. This would be a very risky purchase because in most cases the biggest reason that a manufacturer doesn’t provide this information is because the quality of the materials are low.
Post #4 here has more about the information and specifications you would need (or I would need) to make any kind of meaningful assessment about the quality and durability of a mattress, identify any weak links, and to make meaningful comparisons with other mattresses. I would completely avoid any mattress where this information isn’t available to you unless you are comfortable with a very high risk purchase or the durability or useful life of a mattress isn’t an important part of your personal value equation (such as a mattress for temporary use or for a guest room that is only used occasionally)
While it’s not likely you will be able to find it out … if you can provide this information and post it on the forum I’d be happy to make some comments about the quality of the materials inside it.
Some of the better options and possibilities I’m aware of in the Toronto area are listed in post #1 here.
Phoenix