Hi pacoweaz,
Welcome to the Mattress Forum! 
While I can certainly help with “how” to choose … It’s not possible to make specific suggestions or recommendations for either a mattress, manufacturers/retailers, or combinations of materials or components because 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”, firmness, or PPP or how a mattress will “feel” to you or compare to another mattress based on specs (either yours or a mattress), sleeping positions, health conditions, or “theory at a distance” that can possibly be more reliable 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).
The first place to start your research is the mattress shopping tutorial here (there is a condensed version of it at the end of that post) which includes all the basic information, steps, and guidelines that can help you make the best possible choice … and perhaps more importantly know how and why to avoid the worst ones. Two of the most important links in the tutorial that I would especially make sure you’ve read are post #2 here which has more about the different ways to choose a suitable mattress (either locally or online) that is the best “match” for you in terms of “comfort”, firmness, and PPP that can help you assess and minimize the risks of making a choice that doesn’t turn out as well as you hoped for and post #13 here which has more about the most important parts of the “value” of a mattress purchase which can help you make more meaningful quality/value comparisons between mattresses in terms of suitability (how well he will sleep), durability (how long he will sleep well), and the overall value of a mattress compared to your other finalists based on all the 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 if your choice doesn’t turn out as well as you hoped for).
When assessing any product, also be sure that you find out information listed here so you can compare the quality of the materials and components to the durability guidelines here to make sure there are no lower quality materials or weak links in a mattress that would be a cause for concern relative to the durability and useful life of a mattress before making any purchase.
If you’re too overwhelmed in going through the entire mattress shopping tutorial, then in its simplest form … choosing the “best possible” mattress for any particular person really comes down to FIRST finding a few knowledgeable and transparent retailers and/or manufacturers (either locally or online) that sell the types of mattresses that you are most interested in that are in a budget range you are comfortable with and that you have confirmed will provide you with the all the information you need about the materials and components inside the mattresses they sell so you will be able to make informed choices and meaningful comparisons between mattresses and then …
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Careful testing (hopefully using the testing guidelines in this tutorial) to make sure that a mattress is a good match for you in terms of “comfort”, firmness, and PPP … and/or that you are comfortable with the options you have available to return, exchange, or “fine tune” the mattress and any costs involved if you can’t test a mattress in person or aren’t confident that your mattress is a suitable choice.
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Checking to make sure that there are no lower quality materials or weak links in a mattress you are considering relative to your weight/BMI range that could compromise the durability and useful life of the mattress (see the durability guidelines linked above)
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Comparing your finalists for “value” based on #1 and #2 and all the other parts of your personal value equation that are most important to you.
Having a high BMI presents special challenges and generally requires firmer materials (in the support layers especially). This could be firmer latex or innersprings (the type of support component would be a personal preference and in the right design either could be suitable) or even a zoned construction. The same overall guidelines apply with higher weights though that PPP (Posture and alignment, Pressure relief, and Personal preferences) along with using high quality durable materials that will maintain their feel and performance for longer periods of time are the way to make the best choices. Heavier people in general will need firmer and thicker comfort layers and firmer support layers than those who are lighter and because no materials will last as long with much higher weights the quality and durability of the materials and components is even more important than normal. I wouldn’t “rule out” any types of mattress and base your choices on your own personal testing. Post #3 here and the links it contains has more information and suggestions about heavier weights that is worth reading.
Having a higher BMI, you’ll “go through” the upper comfort layers (the ones that have the most dramatic impact upon your initial comfort) much easier than someone who has a lower BMI. Therefore, it is imperative that these upper layers, which get the most use and wear out the fastest, be as durable as possible (per the durability guidelines linked to earlier) and the higher BMI guidelines linked to above in post #3.
In very general terms … the materials, layers, and components of a sleeping system that are closer to your skin will have a bigger effect on airflow, moisture transport, and temperature regulation than materials, layers, and components that are further away from your skin and softer mattresses or foam toppers will tend to be more “insulating” and for some people can sleep warmer than firmer versions of the same material.
Unfortunately, it’s not really possible to quantify the sleeping temperature of a mattress for any particular person with any real accuracy because there are so many variables involved including the type of mattress protector and the sheets and bedding that you use (which in many cases can have just as significant an effect on sleeping temperature as the type of foam in a mattress) and on where you are in the “oven to iceberg” range and because there is no standardized testing for temperature regulation with different combinations of materials … there is more about the many variables that can affect the sleeping temperature of a mattress or sleeping system in post #2 here that can help you choose the types of materials and components that are most likely to keep you in a comfortable temperature range, provided again that they meet with your BMI durability requirements.
Good – keep working on it. As I’m sure you’re well aware, there is a direct correlation between sleep apnea and heart issues.
You may not have seen my comments on the Helix mattress, so I’ll repost them here for you.
Helix Sleep is another new entry into the simplified choice category that launched in August, 2015. I have talked with the 3 founders and they consulted with a well known group of PHD’s and researchers in sleep ergonomics and have designed a rather unique mattress that uses a customizable combination of 3 different comfort/transition layers that includes 2" of blended Dunlop latex in one of three different firmness levels, a 1.5" microcoil, and 2" of 1.8 lb polyfoam also in one of three different firmness levels. They use a questionnaire with their customers that takes information such as BMI, body measurements, and sleeping positions into account and use an algorithm to choose the order and firmness of each of the comfort layers that are most suitable for each of their customers. The 3 comfort layers are on top of two layers of 1.5 lb polyfoam with two different firmness levels. They can also build a side to side split with different combinations and firmness levels on each side of the mattress for couples with different needs and preferences. They use good quality materials that would be suitable for most weight ranges in terms of durability but I would add a caution for higher weight ranges (more than about the lower 200’s or so).
While other people’s comments about the knowledge and service of a particular business can certainly be very helpful … I would always keep in mind that you are the only one that can feel what you feel on a mattress and I would be cautious about using anyone else’s suggestions, experiences or reviews on a specific mattress (either positive or negative) or review sites in general as a reliable source of information or guidance about how you will feel on the same mattress or how suitable or how durable a mattress may be for you. In many if not most cases they can be more misleading than helpful because a mattress that would be a perfect choice for one person or even a larger group of people in terms of comfort, firmness, and PPP may be completely unsuitable for someone else to sleep on (even if they are in a similar weight range), especially with you and your wife’s differences in size. In other words … reviews or other people’s experiences in general won’t tell you much if anything about the suitability, quality, durability, or “value” of a mattress for any particular person (see post #13 here).
Posts #1 and #2 in this topic also includes more information about the new "breed’ of “simplified choice” mattresses (aka “one choice fits all” or “universal comfort” or “bed in a box” or “disruptor” or “millennial” mattresses) that are available online as well that are typically in a budget range of between $600 and $1000 (queen size). For those that have a more restricted budget then post #4 here and the posts it links to also include many of the better lower budget online options I’m aware of as well.
If none of those options look attractive to you or fit with your BMI / price range, then use the expertise of the members listed in post #21 here who are all very experienced and knowledgeable and specialize in providing the type of help and guidance on the phone that can help you make good choices. There are a wide range of latex and memory foam and other options included in the choices there and I believe that all of them compete well with the best in the industry in terms of their quality, value, service, and transparency.
You may have a better chance of finding an innerspring option by staying local. The better options or possibilities I’m aware of in the Madison, WI area (subject to the quality/value guidelines here) are listed in post #5 here.
I’ve tried to be simple and break out your individual concerns as to not be too overwhelming so that you can go back to this post as a reference for learning about each concern that you brought up. I hope that it helps “simplify” things as much as possible as you go through this process.
I’ll be interested to learn of your progress and what you eventually decide to do.
Phoenix