Hi Advocate,
Welcome to the Mattress Forum! 
Both of the Urban Mattress mattresses you mentioned seem to use good quality materials, but I have a question about the complete specifications of the Dahlia which you’d want to confirm with Urban Mattress.
The Dahlia is listed as having 2" of 28 ILD laters, then a thin .4" of latex, then a 1.5" layer of 2 lb “natural” foam. There is not polyfoam that is “natural”, so you’d want to confirm exactly what that layer is, and how it differs from the quilt foam in the Silver Lake. Also, you’d want to confirm what is quilted to the covering in the Dahlia (if it is just wool or if there is some other unlisted foam). There may also be a difference in the natural of the latex used in each mattress – the Dahlia is listed as a more “natural” item, so you’d want to find out if all of the latex used is natural or blended for sake of cost comparison. The Dahlia is also rated as just a bit more plush than the Silver Lake Plush, but your own personal testing would be the most reliable indicator of your comfort preference here.
Regarding the covering, bamboo just means that some of the fiber used in the cover of the mattress uses bamboo as the precursor for the viscose-dope used to create that fiber. Bamboo does have a softer hand.
Wool is one of the best temperature-regulating materials, and it does offer a unique comfort layer, and it is also good at humidity temperature regulation. There is a bit more about some of the items that can impact your sleeping temperature in this post that you may also find interesting.
Overall, the addition of the wool and the bamboo covering can add to the cost of one mattress versus another, but I would also want to get more complete information about all of the comfort layers in the Dahlia in order to make a more objective comparison between the two items.
Once you have that information, feel free to post it back here and I’ll be happy to comment further upon it for you.
Phoenix