Hi Dragon88,
It sounds like you’ve done some good research and as you probably know Oklahoma Mattress is one of the members here which means I think very highly of them (and Jim the owner) and I believe that they compete well with the best in the industry in terms of their quality, value, service, knowledge, and transparency so you are certainly dealing with a great manufacturer.
I also agree that testing mattresses with a suitable pillow is an important part of the testing process.
[quote]I have narrowed down my choices to 2 mattresses. The first is all Talalay latex with a 4"firm support layer topped with 2" of medium Talalay and 2" soft Talalay. The second is a gentle firm innerspring mattress with a 3"soft Talalay topper. Both beds feel wonderful to me, and I don’t know how to decide between the two. Of course the latex is more expensive, but that, fortunately, isn’t an issue.
Could you please weigh in to help me tip the scales in one direction or the other? [/quote]
There is more about the 3 most important parts of the “value” of a mattress purchase in post #13 here which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well you will sleep), durability (how long you will sleep well), and the overall value of a mattress compared to your other finalists based on suitability, durability, and all the other parts of your personal value equation that are most important to you (including the price of course and the options you have available after a purchase to fine tune the mattress or the exchange return options that are available to you).
In terms of comfort and PPP (Posture and alignment, Pressure relief, and your Personal preferences) which is always the most important part of the “value” of a mattress purchase … the first “rule” of mattress shopping is to always remember that you are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved that are unique to each person to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components or which type of mattress would be the best “match” for you in terms of “comfort” or PPP or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing (hopefully using the testing guidelines in step 4 of the tutorial) or your own personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
In terms of quality and durability … both of the mattresses you are considering use high quality materials and there are no lower quality materials or weak links in either of them.
There is also more about how innerspring support cores compare to latex support cores in post #28 here and more details yet in post #2 here but assuming that the materials in a mattress you are considering are durable enough for your body type (which they are) then the choice between different types and combinations of materials and components or different types of mattresses (see this article) are more of a preference and a budget choice than a “better/worse” choice.
Once you are down to a list of finalists and you are confident that they would all be a good match for you in terms of PPP (or you have good options after a purchase if you aren’t) and that there are no lower quality materials or weak links in any of them in terms of durability (which there aren’t) then you would be down to finalists that are comparing “good to good”. If there are no clear winners between them at this point (which is usually a good indication that you have done some very good research) then you are in the fortunate position that any of them would likely make a good quality/value choice and (post #2 here) can help you make a final choice based on your local testing or mattresses you have slept well on, your more detailed conversations with each of them, your confidence about PPP and the suitability of each one, their prices, your preferences, the options you have after a purchase to fine tune the mattress or exchange or return the mattress or individual layers, any additional “value” extras that are part of each purchase, and on “informed best judgement” based on all the other objective, subjective, and intangible parts of your personal value equation that are most important to you. Sometimes a final choice may even come down to very minor differences or can sometimes just be a matter of “gut feel” or “educated best judgement”.
I’m looking forward to finding out what you end up deciding 
Phoenix