Hi Jdavis37,
While you’ve probably already found this … I’ll include a link to some of the better options in the Charlotte NC area (listed in post #2 here and which includes one of the members of this site) for the benefit of those who may read this thread in the future.
There is more information about natural and organic latex (and blends) in this article and in post #6 here. If you are looking at Talalay … then the blend is actually 60% - 70% synthetic (depending on the latex manufacturer) not the other way around. Dunlop can have many variations between the blend ratio of natural and synthetic. There is very little difference between 100% natural Dunlop and “organic” Dunlop besides the extra cost of certifying the latex for the benefit of those who may value the actual certification itself rather than any meaningful performance differences between the two.
The suitability of a layer would have more to do with its softness/firmness and how it responded to your body weight and sleeping positions in combination with the other layers of the mattress (unless of course the type of latex was more important than its performance). My personal thoughts are that blended Talalay and 100% natural Dunlop are probably the best overall “value” in latex for the typical needs and preferences of most people with blended Dunlop being a good lower cost alternative to more expensive 100% natural Dunlop for those that are comfortable with the tradeoff between lower quality/performance (compared to other types of latex) and price.
The most accurate method of testing a mattress to find out how it meets your specific and unique needs and preferences is local testing (preferable with the help of someone with the knowledge and esperience to provide some good guidance).
If there are few sources available locally that are in the same “value range” … then an online purchase can make sense (I usually use about a 20% local “premium” as being comparable value to offset the increased risk of an online purchase but this would depend on each person’s risk tolerance). It is still beneficial to test mattresses locally however to get a clearer sense of the layering that may work best for you and which can act as a rough guideline for an online purchase (if the comfort specs of the mattresses you are testing are known which may not be the case because unlike “quality specs” these are not important with a local purchase where you can test the mattress). Some of the factors that may be important in knowing the different options that may be an important part of your “value equation” regardless of where you choose to make a purchase are in post #2 here.
A knowledgeable person with good experience will know what to suggest for your body type and sleeping positions and also any special considerations that may be important to you. If this is locally … it can be based on your actual experiences with testing mattresses. If it is online their suggestions will be based more on “averages” of other people in their customer base that may be similar to you. The more knowledgeable and experienced they are … the more helpful and “accurate” their guidance may be.
You have some very good choices within reasonable driving distance 
Phoenix