Hi Smccormick22,
You can see my thoughts about Northwest Bedding in post #10 here and I do believe that they are committed to making higher quality mattresses than the more common mainstream choices.
It’s great to see you are tracking down the specs for the mattress although it’'s actually the job of the retailer to do this for their customers. If you are doing it yourself though I would always make sure you get this directly from the manufacturer (or from the retailer calling the manufacturer) so that you know it’s accurate because mattress specs can change over time and the most accurate source is always the manufacturer themselves. I don’t know the specifics of their mattresses outside of what is on their site…
I believe that they get all their springs from Leggett & Platt so they would be tempered yes. Again though it’s always best to confirm this type of information directly with the manufacturer.
Unfortunately the rest of the specs will need to wait till you call them but once you have them I’d certainly be happy to share my thoughts about them or help identify any potential “weak links” if you list them on the forum.
Phoenix