Any experience with them? Would a 9 inch or 12 inch be the same for a 200lb person? Does Dunlop or Talalay matter? What would be the recommended layers (softness, material etc) for a typical person?
Foam Sweet Foam is one of the members of this site which means that I think very highly of them and that I believe that they compete well with the best in the industry. They use high quality materials in all their mattresses (organic Dunlop latex or 100% natural Talalay latex along with cotton and organic wool quilted covers. A forum search on Foam Sweet Foam (you can just click this) will bring up more information and feedback about them although it will also include some results that include “foam” and “sweet” that aren’t about Foam Sweet Foam. Searching foamsweetfoam will bring up a smaller list of results (that may also miss some) and a search on FSF will bring up results that were missed from the first two searches.
While you wouldn’t “need” 12" of latex at your weight … there are some who would prefer it because thickness is one of many factors that can affect how a mattress “feels” and performs. There is more about the effect of thickness in post #14 here.
They are different from each other so the choice between Dunlop and Talalay would be a preference choice. There is more about the differences between them in post #7 here.
When you can’t test a mattress in person (or a mattress that is virtually identical) then the best source of guidance will be a more detailed conversation with the manufacturer themselves where they can help “talk you through” the options they have available that would be the best choice for different body types, sleeping positions, and personal preferences in terms of PPP . They will know more about the materials and the options they have available and which of them would have the highest chance of success based on “averages” than anyone else (see mattress firmness/comfort levels in post #2 here).