Hi Jiggerjuice,
If you are designing and building your own mattress out of separate components and a separate cover then the first place I would start is by reading option 3 in post #15 here and the posts it links to so that you have realistic expectations and that you are comfortable with the learning curve, uncertainty, trial and error, or in some cases the higher costs that may be involved in the DIY process. While it can certainly be a rewarding project … the best approach to a DIY mattress is a “spirit of adventure” where what you learn and the satisfaction that comes from the process itself is more important than any cost savings you may realize (which may or may not happen).
You can read more about Ultimate Sleep in this topic and I would be very cautious here because I don’t believe they are selling Talalay latex.
The synthetic latex in the Freedom mattress is made by Mountaintop foam and like all latex is a good quality and durable material. There is more about the different types and blends of latex in post #6 here but in very general terms synthetic latex will be less resilient and less “supportive” (it doesn’t get as firm as quickly with deeper compression) than 100% natural Dunlop. It will also be less resilient than Talalay latex (although again the Ultimate Dreams layers are also mostly synthetic Dunlop latex). There is also more about the difference between Talalay and Dunlop in post #7 here.
The Freedom mattress also includes a good quality quilted cover which is an important part of a mattress and with the different firmness levels on each side of the quilted cover there are 12 different ways that you can customize the support and comfort of the mattress. Dreamfoam also has a good return policy (see the bottom right corner of the Dreamfoam site) if for some reason none of the layering arrangements are a good match for you. They also have a 10% discount available at the moment (see their facebook page here). IMO … this would be a less “risky” choice where most importantly of all you would know what you are buying and it includes every component that you need to make a mattress.
The component post here includes the better sources I’m aware of for Talalay latex if you would prefer to use it in your mattress. The layers you listed at foamsource are 100% natural Talalay which is a more costly material than blended Talalay as well.
If you had the same layers (same type and blend of latex in the same firmness level and layer thicknesses) and the same cover then they would be functionally the same yes. If any of the materials or components were different (including the cover) then they wouldn’t no.
Phoenix