Hi tommyboy,
First about the latex allergy … it may be fine depending on the type and severity of the allergy you have. There is more about latex allergies in post #2 here.
The first thing I would suggest is to read the post that is linked after my signature in all my posts along with the information it links to. When you are buying a mattress … especially locally … it’s important to spend a minimum of 15 minutes (completely relaxed) on any mattress you are seriously considering to test specifically for pressure relief (see this article) and alignment (see this article along with post #11 here). Good testing … especially with some good guidance … along with erring on the side of firmness rather than softness can increase the odds dramatically of choosing a suitable mattress or in the worst case a mattress that can be “fine tuned” with a mattress pad or a topper.
With your weight and multiple sleeping positions … it becomes very important that your support layers are firm enough but perhaps more importantly that your comfort layers are also as thin and firm as possible. In other words … “just enough” but no more is the key so that you have the pressure relief you need on your side but still have good alignment on your back and stomach. If the layers are too thick and soft for your sleeping positions … then it may be good for your side sleeping but could present real issues for your other positions … especially on your stomach which is a very risky sleeping position and needs the thinnest and firmest possible comfort layers. What happens is that the heavier parts will “sink through” the soft layers too far but the lighter parts of the body will still be held up with the thicker layers of softer materials. The twisting of your head and neck when you are sleeping on your stomach can also present real issues for stomach sleepers if the layers are too thick and soft. Most of your body weight is in the middle third of your body and this area can sink in more than the wider and lighter upper body if they are not “stopped” quickly enough by firmer support layers.
I would avoid any pillowtops which tend to use way too much lower quality foams on top which will quickly soften and break down and can also allow your heavier areas to sink in too much but still hold up your lighter areas (poor alignment). I would also avoid major brands who tend to use too much lower quality materials in the most important upper layers of their mattresses and charge higher prices for the same or lower quality than smaller local and independent manufacturers.
Your pillow is also an important part of neck issues. Different sleeping positions have different needs when it comes to pillows so they can keep the head and neck in good alignment and if you sleep in all positions then a pillow that can adapt to all positions (thicker and firmer for side sleeping and much thinner for stomach sleeping) is important. many people that sleep in multiple positions do well with a pillow that can be “scrunched” into different thicknesses as they change positions. A side sleeping pillow is not good for stomach sleeping.
There is more pillow information and links in the pillow thread here.
Some of the better possibilities in the Raleigh/Durham area are listed in post #6 here.
It’s true that OMF doesn’t allow for refunds but they have what I consider to be a very fair exchange policy. You can read more about it and my thoughts about refunds and exchanges for a local purchase at the end of post #4 here.
While I do like manufacturers or stores that have a reasonable charge involved in a mattress exchange that covers their costs (so they don’t have to sell their comfort exchanges to liquidators that sell them as new “overstock” or “scuffs” etc or worse yet resell them as new themselves) or manufacturers who change out a layer or make other comfort adjustments to a mattress for a reasonable cost … I’m not a fan of free comfort exchanges or refunds for a local purchase because these add a hidden cost to all the mattresses in the store and are often just a way to discourage customers from doing good testing and locking in a purchase with the “closing technique” of "don’t worry you can always exchange it for another mattress.
What can also happen in these cases is that the “comfort exchange” is a new profit center because of costs involved along with giving credit for a “sale price” which is then applied to a new mattress at it’s “regular” highly inflated price.
I am not a fan of “free” comfort exchanges or refunds for local purchases because they add too much to the cost of the mattress and then people who don’t need to return a mattress are paying for the ones who do. They also flood the market with used mattresses that are being sold as new either through liquidators or through the same store. I think good testing and policies like OMF (where you are getting an exchange for a reasonable cost rather than free) or purchases from a manufacturer or retailer who can change out a single layer or make other fine tuning adjustments to a mattress are a much better option that has much less effect on the cost of a mattress and on the likelihood that you end up buying a used mattress.
Of course with an online purchase where you can’t test a mattress first then it’s a different story and refund and exchange policies can be an important part of the “value” of a mattress purchase in this case.
Phoenix