Hi Debbiec,
Welcome to the Mattress Forum! 
Trying to create your own DIY mattress (like potpot) can be quite a challenge, as I outline in post #15 here. Such projects should be entered into with more of a “spirit of adventure”, with satisfaction coming not only from the completed mattress, but the process itself, as it can be quite a challenge when purchasing foam pieces from various suppliers.
When you’re considering a component-style system, unless you have a large amount of experience with things such as mattress design (which would be very few individuals), I’ll recommend that you follow the guidance from an experienced mattress manufacturer (in your case, SleepEZ, a site member here, which means that I think highly of them) through a detailed phone conversation. You can relate things such as your specific needs, body type, pre-existing conditions, expectations, products you’ve tried and liked, etc., and they can take that information and using their expertise recommend a configuration in their offerings that they feel will provide you the best chance at success. They will know more about “matching” their specific mattress designs, options, and firmness levels to different body types, sleeping positions, and preferences (or to other mattresses that they are familiar with) than anyone else, and at that time you can also inquire about any return/exchange options that a manufacturer/retailer may provide in case you purchase doesn’t turn out as well as you had hoped. Being able to exchange layers, and not the whole mattress, is one of the advantages of a component-style system.
[quote]If I understood correctly sleepez charges same price for all talalay or Dunlop and talalay. I am confused[/quote].
Their “Natural Line” allows for combinations of blended Talalay or 100% Natural Dunlop. Their “Organic Line” allows for combinations of 100% Natural Talalay or GOLS-certified (Organic-certified) Dunlop. Talalay and Dunlop have different characteristics, and that again could be relayed to you when you phone SleepEZ in any configuration that they may recommend, and why they would have advised for a certain type and softness of latex within a specific configuration.
Most people that are looking for an “organic” mattress or materials are usually concerned more with “safety” than whether the materials have an actual organic certification and they usually aren’t aware that an organic certification isn’t the same thing as a safety certification. There is more information about the three different levels of organic certifications in post #2 here and some of the benefits of an organic certification in post #3 here and there is more about the different types of organic and safety certifications such as Oeko-tex, Eco-Institut, Greenguard Gold, C2C, and CertiPUR-US in post #2 here and more about some of the differences between organic and safety certifications in post #2 here and there are also some comments in post #42 here that can help you decide whether an organic certification is important to you for environmental, social, or personal reasons or whether a “safety” certification is enough.
Phoenix