Hi BRZ,
Thank you for taking the time to post the information provided to you by Addable and also providing your feedback about their promptness of response. As you know, Addable Mattress is a member of this site, which means I think highly of them and their transparency. The mattress you described uses good quality materials and there are no “weak links” in this mattress, although I would be cautious for those above 200 pounds or so.
Their support guidelines dovetails with what we’ve been describing, so you’re on the right track in creating your own top-notch slat network! Ironwood Bedframes does make a strong KD foundation that would be appropriate for latex and foam mattresses. Jeff Scheuer from Mattress To Go has posted about them before on the site, as he inspected their product at market and reported back that the foundations he viewed were well-built and commensurate in quality with would be needed for an all-latex mattress. They are currently the company making matching foundation for Pure Talalay Bliss products.
For more information on pillows, you may wish to visit the pillow thread here.
Phoenix