Hi jege41,
Firmness or softness ratings can vary between manufacturers and are also very subjective (different people define firm or soft very differently) so I would be very careful about using any ratings that don’t involve your own personal perceptions unless they can compare it to a mattress or a late firmness level you have tested and are familiar with. I personally wouldn’t count on any help in terms of guidance from the people at Costco because they aren’t what I would call “mattress people”. At the very least I would probably talk with Sleep Science to see if you can get a sense of how well the mattress may match your needs and preferences. If you do decide to make a purchase there, you are rolling the dice with an “all or nothing” choice and are dependent on trial and error in terms of how you feel about the mattress. The only benefit of dealing with Costco is that they have a free return policy which lowers the risk of making an unsuitable choice.
Having said that … it’s always better to err on the side of firmness because you can make a mattress that is too firm softer with a topper but you can’t really make a mattress that is too soft any firmer (except to a small degree) without removing the softer layers because the firmer top layers will just compress into the softer layers below them.
The first thing I would do is make sure these are available in Canada because they aren’t listed on the Costco Canadian website.
Each person has their own “value equation” which are all the factors and tradeoffs that are important to them in any mattress purchase. Having said that I would personally want to know more information about the firmness (ILD or density) of the latex and also the density of the polyfoam base layer so I could “match” it to some local testing as a reference point.
I also place a high value on who I buy from and the guidance they can provide (or local testing where I can make sure a mattress matches my need and preferences before buying it) which to me is just as important a part of the purchase as the mattress itself. Of course the return policy may make up for this for you.
Vancouver has some good latex options (although I don’t know which if any of them carry a latex hybrid like the Sleep Science but a few calls will find out) and you can see some of the options available to you in post #2 here. I would certainly do some local testing first so you at least have a reference point to use with an online purchase.
I know that this latex hybrid from Mattresses.net (one of the members here) can also be shipped to Vancouver and it may be worth checking to find out the cost of shipping there as well.
With these types of challenges I would place a particularly high value on local testing or good guidance but of course each person has different preferences about what is most important in a mattress purchase. The good news is that if the Sleep Science is available in Canada … then with Costco’s refund policy it is good value but it’s not the first direction I would look for a mattress purchase.
Phoenix