Hi sundance,
While the mainstream industry isn’t particularly transparent about the quality and durability of the materials in their mattresses … there are many good manufacturers and retailers that are happy to share the information in this article with their customers and these are the ones that I would deal with.
Brooklyn Bedding and Sleep on Latex are both members of this site which means that I think highly of both of them and that I believe that they compete well with the best in the industry in terms of their quality, value, service, knowledge, and transparency.
While they sell different types of mattresses … neither one of them have any lower quality materials or weak links that would compromise the durability or useful life of their mattresses relative to any weight range.
As you plan to do anyway … when you can’t test a mattress in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart and who can help “talk you through” the specifics of their mattresses and the properties and “feel” of the materials they are using (fast or slow response, resilience, firmness etc) and the options they have available that may be the best “match” for you based on the information you provide them, any local testing you have done or mattresses you have slept on and liked or other mattresses you are considering that they are familiar with, and the “averages” of other customers that are similar to you. They will know more about “matching” their specific mattress designs and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else.
I’m not clear what you are asking … could you rephrase your question to make it a little bit more clear.
If you are asking about bedframes and foundations then there is more information about support systems (bedframes and foundations or platform beds) that are generally suitable for different types of mattresses and some examples of each of them in post #1 here.
Phoenix