Hi EvanChi,
I would avoid any mattress that uses more than “about an inch or so” of lower quality materials which would include 3 lb memory foam.
If the specs they listed for the Sleep Science Ara here were correct (and assuming that the base layers are also a good quality material) then there would be no lower quality materials or weak links in the mattress but I’m not so sure they are correct because their specs don’t add up to their shipping weight. If the top two layers are really 5 lb memory foam then they would weigh (in queen size) a total of 92 lbs and if the mattress weights 109 lbs (again in queen size) then the base layers would only weight 17 lbs which would be impossible so either the shipping weight is wrong or the density of the foam layers are incorrect.
The specs on the Escape add up to the shipping weight so there would be no lower quality materials or weak links in this mattress so it would be worth considering.
There is also more about buying a mattress from Costco in post #4 here.
These all use high quality materials that would be suitable for your weight range and there are no lower quality materials or weak links in any of them.
I’m not sure which mattresses you were looking at but like every other city the retailers or manufacturers in Chicago would carry a wide range of mattresses from very soft to very firm and everything in between.
There are also no “standard” definitions or consensus of opinions for firmness ratings and different manufacturers can rate their mattresses very differently than others so a mattress that one manufacturer rates as being a specific firmness could be rated very differently by another manufacturer. Different people can also have very different perceptions of firmness and softness compared to others as well and a mattress that feels firm for one person can feel like “medium” for someone else or even “soft” for someone else (or vice versa) depending on their body type, sleeping style, physiology, their frame of reference based on what they are used to, and their individual sensitivity and perceptions. There are also different types of firmness and softness that different people may be sensitive to that can affect how they “rate” a mattress as well (see post #15 here) so different people can also have very different opinions on how two mattresses compare in terms of firmness and some people may rate one mattress as being firmer than another and someone else may rate them the other way around. This is all relative and very subjective and is as much an art as a science.
In other words the only way to know how firm or soft a mattress feels to you and “how” it feels firm or soft (feel firmness/softness, pressure relief or comfort firmness/softness, or support firmness/softness etc) will be based on your own careful testing or personal experience. With your weight at the very least you will need firm support.
That would rule out all the mattresses you mentioned in your last reply although if for some reason that is the only combination of materials that you are considering then the Christeli Palais Grand Royale and Lux Estate would both fit this criteria.
The list I linked in my last reply includes the better options or possibilities I’m aware of in your area.
Phoenix