Hi cpcrn
I don’t make specific recommendations for either the type of latex (this is a preference choice) or the firmness of individual layers because when you can’t test a mattress in person then a more detailed conversation with a knowledgeable and experienced manufacturer will always be a more reliable source of guidance about which of their firmness or layering options would be the best “match” for your specific needs and preferences in terms of PPP or which of the options they have available would be the closest “match” to another mattress than I am. They will know more about the options they have available than anyone else. I would also keep in mind that the two Dunlop layers in the Savvy Rest are specified as a very wide ILD range so if you were to choose a medium layer that is 31 ILD then for most people it would probably feel different from a “medium” layer that is 39 ILD.
There is also more about the different ways to choose a mattress (either locally or online) that is the most suitable “match” for your specific needs and preferences (or to another mattress) and how to identify and minimize the risks of making a choice that doesn’t turn out as well as you hoped for that are involved in each of them in post #2 here.
As I outlined in my previous reply … none of the options you are considering for a single 6" layer (instead of two 3" layers that are a different firmness or ILD) would be exactly the same as the 3 layer Savvy Rest mattress you are testing … but since the upper layers of a mattress will have a bigger effect on what most people feel than the deeper layers … a medium 6" layer that was the same ILD as the middle layer of the Savvy Rest in “real life” (not just somewhere in the same range) would probably be the closest approximation assuming that all the other variables (including the firmness of the top 3" layer and the specifics of the cover) were also very close approximations as well. How much difference you may feel between them would depend on your body weight and your sensitivity to smaller differences in a mattress and where you are in the range between “princess and the pea” and “I can sleep on anything”. Differences that are quite noticeable to some people may not be noticeable at all to others.
If you replace the Dunlop layers you tested with Talalay then the feel would be different yet and the difference between them would probably be even more noticeable for most people even if the actual firmness (regardless of the specified ILD of the Talalay) was the same. There is more about the differences between Dunlop and Talalay in post #7 here.
If a mattress you are considering has a different design or components or different firmness options than a mattress you have tested then choosing which of the options or combinations you have available from any particular manufacturer would be a matter of talking with them and then making a “best judgement” choice about which one is likely to be “close enough” for you because none of them would be exactly the same.
Phoenix