Hi squidgette,
Welcome to the Mattress Forum! 
The Eight Sleep mattress hasn’t been discussed before on the forum, so thanks of bringing them up.
While I’m not personally familiar with the mattress, I can make a few general comments.
Your specifications are a bit incorrect. The top layer is one of the new breed of what I term “high performance" polyfoams, and it is 2” of 12 ILD 3 lb density. They list is as “latex-like” on their web site, and in another section they list it (incorrectly) as “synthetic latex”, but it is polyfoam, Beneath that is 2" of 11 ILD 4 lb memory foam. Under this is a 2" piece of 22 ILD 1.8 lb poly foam and then a 4" piece of 35 ILD 1.8 lb polyfoam (these two layers are not memory foam as you had listed). These would be good quality materials and for your BMI there would be no obvious “weak links” in the mattress. I would provide a caution for someone in the “above 200 pounds or so range” with the 1.8 lb support core and the 4 lb memory foam.
Eight Sleep has a focus on their mattress cover for measuring temperature, heart rate, respiration and movement and then works to connect to other smart home devices such as lights, thermostats, coffee machines, etc. It collects your data and combines it with the data they collect worldwide in an attempt to develop a “sleep algorithm”. Here are a few of their patents.
While I can certainly help with “how” to pick out a mattress, the only way to know for certain whether any specific combination of materials will be suitable for you or which ones you tend to prefer will be based on your own careful testing (hopefully using the testing guidelines in the tutorial ) or your own personal sleeping experience because different people with different body types, sleeping styles, sensitivities, and circumstances can have very different experiences or opinions about whether the same mattress provides “enough” comfort for their own personal preference.
If you do end up purchasing one of these mattresses, I’ll look forward to your comments on it.
Phoenix