I am located overseas, with no local source of latex mattresses. Recently on a trip to the US we had a chance to try out a few latex mattresses quickly in a retail store, and found that the extreme ends of the firm and soft spectrum were too much for us, but the three or four middle of the road models all felt very good. My concern is that after having more time to evaluate we may find we want something slightly firmer or softer. It costs quite a bit of money to ship bulky items such as latex mattress pads here, and I want to avoid having to order an additional layer or exchange a layer in the future. I was looking at a vendor (mattresses.net) who offer two layer models, and purchasing a firm base, with a medium top, and then adding a 2" soft layer on top of that. This would let us mix and match to a degree and get the right feel. Am I on the right track with this thinking? Should I get 3" or 2" toppers and comfort layers?
Me: 180lbs, 5-11", side and stomach sleeper
Her: 190lbs 5-4", side and stomach sleeper
In cases like this it is usually a “safer” approach to choose a little firmer than a little softer because even if there are no latex layers available for fine tuning … other materials (mattress protectors, mattress pads, or toppers) can also be used to “fine tune” a latex mattress and it’s much easier to “fix” a mattress that is a little too firm than too soft.
I usually leave the specific recommendations for a mattress up to your conversations with each manufacturer because they have much more knowledge than I do of the exact materials, components, and layering choices that they offer or have available and how they interact together and may fit different body types, needs, and preferences of their customers. These recommendations in other words are specific to their mattresses and can take into account more information than just height/weight and sleeping positions, any specific feedback and information you can provide about mattresses you have tested or slept on, and their experience from the feedback of their customer base that can provide reference points to customers that are similar to you in the absence of specific testing.
In general though … I would say you are taking a good approach but without a reference point of the specific mattresses you have tried (such as the exact layering that you found either too soft or too firm because these are subjective terms) … there is really no way to know which type of layering may work best for you except by using “averages”. These “average” recommendations may be different between different manufacturers (based on their experience and knowledge of the specific options they have available).
Having said all that … your suggested layering of a firm 6" base with a medium 2" layer and then a soft 2" layer seems to me to be in the ballpark of what would work for both of you but it would also depend to some degree on what you (or the manufacturer you are working with) were calling firm, medium, or soft … on the cover and quilting you used … and on the type of latex you were considering. It would give you the option of using soft over medium or medium over soft (the firm would likely always be on the bottom) so you would have two layering patterns available with these layers. The advantage of a thinner “soft” layer is that it may be more suitable for stomach sleeping because you would “reach” firmer layers more quickly with less risk of hammocking.
If you choose a thinner comfort layer (such as 2") it may involve choosing slightly softer layer below it to “compensate” for side sleeping and if you are choosing a thicker comfort layer (such as 3") then this may involve choosing a firmer layer below it to “compensate” in the other direction. The choice would depend on the ILD’s they have available and on what they think will work best. Again … without specific reference points of mattresses you have tried and liked … then the “averages” that are recommended by each manufacturer based on their experience and the feedback from other customers that may be somewhat similar to you would have the best odds of success for the mattresses they offer.
So in very general terms … it seems to me that your suggested layering would be a good compromise for stomach sleeping. It would have a thinner soft layer for stomach sleeping (reducing the risk of sleeping in a “swayback” position) and a thinner medium transition layer (which will “allow” some extra softness for side sleeping) all over a firm base layer.
The choice between 2" and 3" toppers would depend on the specific details of each layer and component in the mattress and how each of them may interact with each other and your specific needs and preferences (in other words 3" layers could lead to different firmness choices than 2" layers) but it seems that you are certainly “within the averages” that could work for you.