Hi deepcreek,
Welcome to the Mattress Forum! 
I’m glad you’ve found us and that the information here has been helpful.
I think that you may have already found this information, but 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, but all of the layers of a mattress work in unison, so I wouldn’t necessarily say that you need 3" of comfort material in every configuration, but as I stated people with a higher BMI do generally need thicker comfort layers. I wouldn’t “rule out” any types of mattress and base your choices on your own personal testing. Post #3 here has more information and suggestions about heavier weights that is worth reading (if you haven’t already read it).
The Brooklyn Bedding BME is now using a 1.8 lb polyfoam core, but they went to a higher ILD, and Mario from Brooklyn Bedding has stated that their testing results show a similar durability of their 1.8 lb at a 36 ILD to a 2 lb polyfoam at a 30-34 ILD. You can see Mario’s note about the new BME in post #26 here. )You are correct that I like to see a 2 lb density for higher BMIs for polyfoam.) You’d want to contact BB before making an order, but with their three different comfort designations, they would most likely recommend either their Firm or Medium configurations, the Medium using 2" of 18 ILD and 2" of 28 ILD TitanFlex 4 lb high performance polyfoam, and the Firm using 4" of 28 ILD TitanFlex 4 lb high performance polyfoam in the comfort layers.
The Dreamfoam Ultimate Dreams EuroTop Latex Mattress uses an 8" 2 lb polyfoam core, on top of which is a selectable ILD of Talalay latex (you would consult with them when placing your order for the recommended ILD), and 1.5" of plush polyfoam in the quilt. On their scale of 1-10 (1 being firmest, 10 being the most plush), they would probably have you in the lower end of that spectrum. They also have the ability to swap out the latex layer. Overall the polyfoam core is slightly denser than that of the BME (I don’t know the ILD of the polyfoam core of the UDET), and the latex would generally be a more durable type of foam, but I wouldn’t be able to predict which model you might find more comfortable.
As Dreamfoam is a sister company to Brooklyn Bedding, I would phone them and let them know which two models you are considering and see if they have any specific advice and if they feel that one model if preferable over the other for someone of a higher BMI. They would have more knowledge and a larger database of reference of similar consumers and feedback on how their products performed in such applications.
I’ll be interested in learning if you make a decision or any other questions you may have.
Phoenix