MWard86,
I’m not Phoenix but I can throw in a few comments that you may find helpful.
Places like MBA have been discussed previously here on the forum. You’re correct that they feature the typical brands you mentioned, many which tend to use lower density foams. Follow the advice Phoenix presented in the reply I linked to as far as what questions to ask (it’s unlikely you’ll get accurate answers to your foam density questions, but here’s hoping you will) and to not fall prey to “special offers just for you today” nonsense (see this video).
As for your contact with King Koil, phoning them at their corporate offices wouldn’t be the way to get information about their product - that’s something that you should procure from your local retailer and that’s part of their responsibility (should they have that information or choose to share it with you). The corporate offices aren’t set up generally to deal with consumers, but instead to interact with retailers directly. If you’re not getting good answers to your questions about the basics such as product componentry, then you may wish to move on and search for a new retailer.
Jeff Scheuer, The Beducator
Beducation / Mattress To Go