Hi ATLTiger,
Certainly both foundations would work for your current mattress. The wood foundation overall would be stronger. The metal foundation (Simple Life) can not be refolded once it is opened up. The wood foundation can be disassembled and moved. The US Box Spring foundation you mentioned would also be a good option.
I’m not sure what you mean by “non-toxic” options. “Toxic” is a term for poisonous substances produced within living cells or organisms, although the term is often used in the mattress industry (and often part of some “fear-mongering” campaigns), but I think I understand your point. Most people that are looking for “non-toxic” (toxicity is dose-dependent) materials are usually concerned most with “safety”.
As there is quite a bit of confusing information available online about toxicity, safety and organic, there is more about the different types of organic and safety certifications such as Oeko-tex, Eco-Institut, Greenguard Gold, C2C, and CertiPUR-US in post #2 here, and more about some of the differences between organic and safety certifications in post #2 here and there are also some comments in post #42 here that can help you decide whether an organic certification is important to you for environmental, social, or personal reasons, or whether a “safety” certification is enough, and what those certifications can mean to determine whether the contents of any particular mattress are “safe enough” for you.
The most common foundations used for a one sided mattress are wood, metal, or a combination of both, and for most people they are considered “safe”. As far as all of the offerings out there, I don’t keep track of the thousands of foundation offerings available in-store and online, as that would be an impossible task for one person in a constantly changing environment.
Phoenix