Hi Mightyh,
Thanks for taking the time to write such a detailed review and sharing all the steps of your process with us. I appreciate it.
You certainly made a great choice that was well thought through.
You can see some of the tradeoffs between the different types of mattress protectors in post #89 here.
In terms of “feel” the Natura is the thickest and would probably have the biggest effect on the feel of your mattress. The Dormeir is thinner and more stretchy and would have less effect and a stretch knit cotton would have the least effect.
The Dormeir has wool so it would have a bigger effect on regulation temperature than cotton and it would also be more water resistant (it’s not water “proof” though) than cotton.
Overall if both temperature regulation and feel were most important then I would probably go with the Dormeir.
I have the Natura Deluxe Protect which is similar to the Dormeir except it has the waterproof/breathable membrane and while it’s fine … if I had to do it over again I would probably choose the Dormeir both because it’s more stretchy and because water resistant is fine for me and is more breathable than having a waterproof membrane.
If only the feel was important along with the ability to protect from body oils then a stretch knit cotton would probably have the slight advantage (like having a thick stretchy sheet) but at the cost of water resistance and the temperature regulation of wool (although it is also very breathable).
Congratulations on your new mattress 
Phoenix