Hi burly,
In case you haven’t read it yet … the first place I would start your research is post #1 here which hs all the basic information, steps, and guidelines that you will need to help you make the best possible choices … and avoid the worst ones (including Kingsdown or any manufacturer that doesn’t provide information about all the materials in their mattresses).
Assuming you’re in or near Sacramento … the better options or possibilities I’m aware of are listed in post #5 here.
If you’re not in reasonable driving distance of the choices there then if you let me know your zip I can give you a link to any of the forum lists that may be closer to you.
Phoenix