Hi datwundude.
I am glad you got in touch with Scott to take advantage of the SOL coupon, and yes both SleepEZ and SleepOnLatex use good quality/value materials within their mattresses that would be suitable for high weight ranges.
More and more mattresses are available as a “component-style” system where the layers are not glued and swappable, even split, and configurable before and after purchase. Depending on the mattress design, the “before purchase” part allows the customer to select the type of material (Blended, natural, synthetic, or specialty foams) and firmness (XS, S, M, MF, F, XF) of the layers within the mattress to achieve different comfort levels. The “after purchase” part would allow the customer to fine-tune their mattress by unzipping and opening the mattress cover/encasement to remove one or more layers within the mattress in order to exchange them for different firmness levels without shipping the entire unit back to the retailer/manufacturer. The largest advantage to the component-style system is the ability to customize, replace, and rearrange layers over time to create different comforts or to replace worn out uppermost layer (which usually undergoes the most mechanical stress and is the softest layer within a system). Component-style systems are usually much easier to ship and have layers that can be shipped in separate boxes, but you would need to assemble those on your own. Usually mattressess that are customizable only “before purchase” are made by manufacturers who can “tailor” a mattress to suit particular customer needs (feel, comfort, size, etc.) and are delivered as finished products that cannot be opened and further customized and are more stable (tufted, custom made mattresses for RVs. etc. ) You can read more about the pros and cons of “finished mattresses” that generally have glued layers vs component mattresses with unglued layers and a zip cover in post #15 here and post #2 here.
SOL’s suggestion makes sense for side sleepers. 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. SOL Dunlop is a very durable material but they’ve recently changed the firmness of the top layer for their Pure Green soft version so I suggest that you call once more and make sure that they’ve taken into account your high BMI when they make their recommandation. Post #3 here has more information and suggestions about heavier weights that is worth reading.
The specifications for each of the two options you are considering from SOL are
SOL’s Pure Green Medium Option
2" 20 ILD (of 4 lb/ft[sup]3[/sup]) Dunlop top comfort layer
6" 30 ILD (of 4.9 lb/ft[sup]3[/sup]) Dunlop support layer
… (medium 9" proving to be a better solution for a combo sleeper that spends time on their side and occasionally their back.)
SOL’s Pure Green Soft Option
2" 20 ILD (of 4 lb/ft[sup]3[/sup]) Dunlop top comfort layer 65 kg/m[sup]3[/sup]
6" 22 ILD(of 4.4lb/ft[sup]3[/sup]) Dunlop support layer
…(better choice for a side sleeper)
Of course… Sedona mattress completely slipped my mind, I was totally zooming in on Mattresses.net Thanks for the reminder. 
Phoenix