Hi Miko,
As you can see in mattress firmness/comfort levels in post #2 here … I don’t believe that using “statistics” or “theory” to choose a mattress is a great idea although they can provide some useful generic guidelines. I also wouldn’t use Plushbeds as any kind of “authority” for what may be suitable for you (outside of making a choice between their specific mattresses if you were to make a purchase from them) because every layer interacts and affects every other layer in a mattress. Your own testing or experience (using the guidelines in post #1 here) is the most reliable way to know which mattress is most suitable for you. The choice between Talalay and Dunlop is a personal preference although Talalay is probably more common in comfort layers (not better) only because it tends to be more widely available in softer versions that many people seem to like but this is also not always the case. Both are commonly used in transition or support layers. I personally prefer the feel of Talalay for example but my daughter much prefers the feel of Dunlop in all her layers (including the comfort layers).
When your shoulders feel squished then it often indicates that you may need a thicker or softer comfort layer to “allow” your shoulders to sink in more deeply but this will also depend on the firmness/softness of the layer below it. Softer support or transition layers often mean you can use thinner comfort layers because the top section of the support or transition layer will also be part of your pressure relieving cradle (the depth you sink into the mattress regardless of the thickness of any specific layer and its ability to conform to the shape of your body).
Literie Laurier is certainly one of the better quality and value options available in the Montreal area but there are also others (see post #276 here) that may be worth talking to as well. You are fortunate to have so many good quality manufacturers so close to you.
This would certainly be well worth testing but just as a point of clarity … 1832 polyfoam is 1.8 lb density (the first two numbers) not 2.0 lbs. The last to numbers are the IFD (softness firmness rating) which in this case is 32 (at the bottom of the firm range).
This would also be well worth trying and may provide better support under the pelvis (especially for your stomach sleeping) but I would also make sure that the comfort layer wasn’t too firm for your shoulders to sink in deeply enough when you are on your side. Firmer and thinner is less risky though for stomach sleeping which carries a much higher risk of sleeping in a swayback position which can often contribute to lower back issues. The goal with combination side / stomach sleeping is “just enough” thickness/softness for pressure relief and to allow your shoulders to sink in far enough on your side so that the alignment risk for stomach sleeping is lower ( you are closer to the support layers which will “stop” the heavier pelvis from sinking down too far and hammocking on your stomach). The more time you spend on your stomach over the course of the night the more you may need to “weight” the specific needs of stomach sleeping.
Phoenix