Hi grey01.
Welcome to our Mattress Forum! 
Thank you for the kind words, and I am happy that the information here is helpful to you.
Based upon your commentsI think you’re already on the right track and have a general idea of the types of components you need to look for in your new mattresses. Generally traditional innerspring mattresses are notorious for motion transfer issues for “light” or more sensitive sleepers. Two independent units using two twin extra long mattresses, on separate bed frames and separate foundations is certainly the best way to minimize motion transfer. I am not sure if you gave up totally on the idea of sleeping in the same bed or how motion sensitive you are but … in case you are still considering a common bed … If you’re placing two twin extra long bed sets upon the same frame, you’ll still have some motion transfer but not so much as with a side by side split (needed to accommodate for the difference in feel, BMI, and sleeping positions between partners). Pocket coils are generally good for motion isolation, unlike innersprings that are linked with helicals which are generally poor to fair depending on the specifics of the innerspring and the foam layers above it. Motion transfer easy to test for and it may be worth trying a latex/ or memory foam pocket coils unit or all latex with a side by side dual configuration that would have better motion isolation, Latex is among the least motion transferring of materials second only to memory foam.
Either way, I would certainly suggest to you to rely on the advice of the manufacturer themselves as they are much more familiar with their own mattress designs and materials than anyone else (including me) and they can use the information you provide them about your body type and sleeping positions, your preferences, your history on different mattresses, and the results of your local testing to make suggestions based on the “averages” of other customers that may be similar to you. Before the showroom visit I’d make sure to revisit the tutorial post here which has all the basic information, steps, and guidelines you will need to make the best possible choices … and know how and why to avoid the worst ones which would include the major brands or any mattress where you aren’t able to find out the quality of the materials inside it. With a local purchase for the majority of people … careful testing using the guidelines in the tutorial linked above rather than just testing for the more subjective “comfort” of a mattress (which often won’t predict how well you will sleep on a mattress or how it will “feel” when you sleep on it at home) and some good guidance from a knowledgeable and experienced retailer or manufacturer will usually result in a mattress choice that is well inside a suitable comfort/support range and will generally be “close enough” so that if any fine-tuning is necessary it would be relatively minor and involve different mattress pads, sheets, mattress protectors, or perhaps even a topper if a mattress is too firm (see post #4 here and post #10 here ).
Some good local testing will also give you a much better sense of the many different types of materials and components that are used in mattresses and some reference points about the types of mattresses (see this article) and general firmness levels you tend to prefer which can help you narrow down your choices regardless of whether you end up purchasing locally or online.
Because warranty requirements can vary from manufacturer to manufacturer, I always suggest checking with the manufacturer of the mattress you are considering to make sure that the metal frame you own meets their warranty criteria (or read the warranty)
I am glad that you are visiting Nest Bedding which is one of the manufacturing Trusted Members of this site Like all the memberr of our site they are very knowledgeable and skilled in guiding their customers to make the best possible choices out of the many options they have available.
Also you have some other equally valuable trusted members that are less than one hour driving distance from Palo Alto and South Bay :
Bay Bed & Mattress Santa Cruz, CA
Foam Sweet Foam in Fullerton, CA [/indent]
Like all the members here I think very highly of and consider them to compete well with “the best” in the industry.
I’ll look forward to learning about your progress and of course any other questions you might have.
Phoenix