Hi redliondog,
The OSO is a bit of a unique bed in that is uses latex “Dreamcell springs” in the upper third area of the base of the mattress. The theory is that this area allows you to sink in a bit more. especially if you sleep on your side, and you can spin the mattress so that the latex springs are located either under your shoulders or your hips, depending upon your individual needs and preferences. With this different design, all of the layers work together, but in a bit of a different manner than other mattresses, so your concerns would best be addressed with a phone call to OSO and express your concerns. When purchasing something online that you can’t test, it’s important to learn in advance of any exchange/return policy, and OSO does have a 101 night promise guarantee for a refund if needed.
In general, the thickness of a mattress or the number of layers or the thickness of any individual layers inside it is really just a side effect of the design and the design goals of a mattress and the thickness of any individual layers or the complete mattress is also only one of many variables that can affect the feel and performance of a mattress relative to any particular person (see post #2 here) and by itself isn’t particularly meaningful (see post #2 here). In some cases higher weight ranges (or a higher BMI) will sometimes do better with a mattress that is thicker than lower weight ranges or a lower BMI (see post #14 here for more about the effect of thickness) but even this depends more on the specific design and combination of materials in the mattress and on how well your testing or personal experience indicates the mattress “as a whole” matches your specific needs and preferences in terms of comfort, firmness, and PPP than it does on just the thickness itself.
Reverie (OSO’s parent company) is a member of this site which means that I think very highly of them. I wouldn’t hesitate to phone them and ask their opinion based upon your BMI concerns.
Knowing the ILD/IFD of the deeper polyfoam layers in the mattress isn’t particularly meaningful and not an indicator of quality like density is. Many manufacturers will not disclose the ILD/IFD of their foams as “proprietary” information, even for online retailers. I would consider ILD/IFD information of these polyfoam to be a legitimate part of what many manufacturers consider to be “proprietary” information and it would be completely meaningless and only add to the confusion for most consumers anyway. The density would be the key thing to focus upon.
I’ll be interested to know if you get a reply and see what you find out. Specifically, you’d want to know the density of the 1.5" gel memory foam, the type/blend/ILD of the 2" latex layer, the density of the 1.5" Energex foam (which is a high-performance polyfoam) and the density of the 6" support core.
I should also add that their comments about “markups” on their site are also very misleading (other online sites do this as well - see this topic) and “normal” markups or margins are nowhere near what they are claiming they are.
I’ll look forward to learning about your progress.
Phoenix