Hi stanleychs1437,
The Mattresses.net adjustable ultra plush would be more closely comparable to the SleepEZ 8" special here (which also has 8" of latex) except the 8" special has a stretch knit cover that isn’t quilted with wool, it has 100% natural Dunlop in the bottom two 3" layers instead of Talalay, and it uses 100% natural Talalay in the top 2" layer.
It would be closer yet to the SleepEZ 9000 mattress here which has a very similar design and uses the same type of latex except for the difference in the number of layers and the options that are available to customize the mattress and the differences in their exchange policies.
I wouldn’t have any “safety” or health concerns with any type of latex and they are all Oeko-Tex or Eco-Institut certified for harmful substances and VOC’s (see post #2 here).
There is also more about the differences between Dunlop and Talalay latex in post #7 here but this would be more of a preference choice based on which one your own personal testing and/or experience indicates you like better.
As you know I think highly of both of the manufacturers you are considering and you are certainly looking at some great options.
Phoenix