Hi firebluephoenix,
I don’t think that there will ever be anything that can replace either personal testing and experience or the guidance of a retailer or manufacturer that includes their knowledge of the specifics of each of their designs and the feedback from their customers on specific mattresses. There are just too many variables and differences between people for any “formula” to ever replace these IMO.
The better options I’m aware of in the San Diego area are in post #2 here.
Not only does Stearns & Foster use mostly synthetic “smart latex” in their mattresses … for the most part they also include relatively thick layers of polyfoam in the comfort layers which will break down faster than the latex. There have been many examples in the forum of people who experience many issues with them … typically starting at around year 3 or 4.
Yes you hit the nail on the head when you mentioned the warranty exclusions which in the case of major manufacturers means that they are able to avoid the majority of warranty claims.
Is there a reason that you are looking for a mattress / topper combination rather than choosing a mattress that doesn’t need a topper or where you can use a topper as a “backup” for fine tuning in case you make a choice that is a little too firm?
Choosing a suitable mattress can be difficult enough but if you are considering two variables that can interact together in unknown ways without testing the specific combination, then it can be even more difficult to predict how the two together will feel and perform for you.
If you do go in this direction and haven’t been able to test the specific combination together … I would tend to choose a mattress that by itself is as close to your needs and preferences as possible with the “intent” of not having to add a topper at all and then choose a topper (only if you need it) based on your actual experience sleeping on the mattress over the first few weeks or so (after the initial break in and adjustment period is over).
Phoenix