Hi JaridH,
Your pictures are probably larger than the maximum limits for forum image attachments (see here) and you should be able to attach them if you reduce the size to less than 2000kb and to a maximum of 800 x 800 pixels for the width and height. If you don’t know how to reduce them or if you have any other difficulties then you can also email them to me at the contact email at the top right of the page and I can reduce the size and attach them to your post for you as well.
The component list here includes the better online sources for polyfoam that I’m aware of and there are also some comments and comparisons in post #4 here and post #6 here that may be helpful as well.
I don’t know the density of the polyfoam in the bottom layer of your mattress but something in the range of about 2 lbs density should be fine. I also don’t know the ILD/IFD of the Tempurpedic bottom layer or whether they can cut a thicker layer of polyfoam into a convoluted surface but the convoluting wouldn’t be particularly important anyway and they should be able to help you choose a layer that would be a reasonable approximation of the Tempurpedic polyfoam layer you are replacing.
Phoenix