Hi tyfighter,
Welcome to the Mattress Forum! 
The Dreamfoam Ultimate Dreams Total Latex offers a 6" core of 32 or 36 ILD blended Talalay latex from Talalay Global (a Dunlop core may be substituted if desired). The upper 3" layer can be swapped out and ordered in various plushnesses of the same Talalay latex. You would phone Dreamfoam Bedding prior to placing an order to determine which plushness (ILD) they think would work best for you. There is a quilt panel with a small amount of polyfoam and wool above the top latex layer. There is an innerpanel between the 6" core and the upper 3" latex layers. I don’t know the exact ILD Dreamfoam would offer for their comfort recommendations of their upper 3" latex layer. They use a 1-10 scale, with 1 being hardest and 10 being softest. In the past they’ve offered 19, 24, 28 and 32 ILDs, and have listed 28 ILD as a 6 on their comfort scale and 32 ILD as a 4 on their comfort scale.
The Berkeley Ergonomics (BE) mattress you tested would be using 100% Natural Talalay latex from Vita Talalay. This mattress you tested uses the same 6" thickness in the core (the BE core can be zoned or non-zoned) as the Dreamfoam, but 2" of Talalay on top versus 3" for the Deamfoam mattress. The cover it uses is organic cotton quilted to organic wool.
Both of the mattresses you asked about use durable and good quality materials.
You can see more about the differences between synthetic (SBR) and natural (NR) rubber in post #2 here.
There is more information in post #9 here about the different ways that one mattress can “match” or “approximate” another one. As I think you’re already aware, every layer and component in a mattress (including the cover and any quilting materials) will affect the feel and performance of every other layer and component and the mattress “as a whole” so unless you are able to find another mattress that uses exactly the same type of materials, components, cover and quilting, layer thicknesses, layer firmnesses, and overall design (which would be fairly unlikely) then there really isn’t a reliable way to match one mattress to another one in terms of “comfort”, firmness, and PPP (Posture and alignment, Pressure relief, and your Personal preferences) based on the specifications of the mattresses (even assuming that you can find out all the specifications you would need for both mattresses you are comparing in the first place).
If you do decide to go with the Ultimate Dreams … I don’t know exactly how their softness rating system works (which ILD they use for each number) but they would be in the best position to give you great advice on the best choice based on your local testing and feedback. A “typical” ILD choice for the comfort layer of a latex mattress would be in the 19 - 24 range with some going softer down to as low as 14 and some going as high as 32. With the quilting foam in the Ultimate Dreams … it would give it a little softer feel than just the ILD of the latex itself. It would effectively bring the ILD down a bit. Dreamfoam is a member here, which means that I think highly of them, their advice and their products.
If you’re looking to consider other options, I would suggest you take a look at 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 component mattresses 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.
Phoenix