More obstacles…
I was doing the math and came to the conclusion that if I bought components separately, I would save myself as little as about $300 compared to buying a pre-made mattress from one of the online member retailers, and I would have more issues with any sort of comfort exchange. So I decided to just bite the bullet and buy the pre-made mattress…
This is what I am looking for:
Top: Talalux blended talalay in ILD 22
Middle: 100% natural dunlop in ILD 25-30 (assumed 75D)
Bottom: 100% natural dunlop in ILD 40+
Unfortunately, I couldn’t find a single online retailer where I could configure a mattress exactly like I wanted. Some (like SleepEZ) could match two of the layers that I was looking for, but not the third. In the SleepEZ case, it is because they do not carry dunlop latex layers in the ILD 25-30 range. I emailed back and forth with one of their reps and learned their dunlop comes from Latex Green, and that SleepComp tests the latex for ILD before distribution. Apparently, SleepEZ only orders certain ranges of ILD, with gaps between them. For example, no ILDs between 24-30 or 32-37.
I understand the “many roads to Rome” theory you’ve talked about, but any “experimentation” with different layering combinations starts to increase the likelihood of having to do an exchange. Since any exchange with most of the retailers involves a fee of some sort, it would increase the cost and the difference between building my own. I’m starting to consider myself the “prince and the pea” since I tried a very similar mattress yesterday that I felt was too firm. The primary difference on that mattress was the middle layer was ILD 30-35, versus 25-30.
So now I am back to buying the components myself, and it looks like I will have to use a couple different vendors. I have started making a list of who carries which of my three layers. My question for you involves the middle layer I am looking for. I have found several vendors selling 100% natural dunlop with an ILD rating that falls somewhere in between 25-30, but several of them also list a density of 5.2 or 5.3 ft/lbs, which I feel is not consistent with that ILD range. Some of these products are here at RockyMountainMattress, SleepWarehouse, and the ErgoSoft products sold on Amazon and elsewhere. All of these dunlop products are made by Latex Green or Latex Systems Co.
I am wondering if I should be looking at the 4.7 or 4.75 ft/lb dunlop products sold by these same vendors. Although the vendors are listing these densities as 16-18 ILD, they are in essence 75D dunlop, which should be in the mid to high 20’s ILD. I really feel that is the case after reading your posts here and here.
I guess my question for you is, which of the vendors’ listed “specs” are likely to be accurate, the density or the ILD? If you were so inclined to be trying to build your own latex mattress, and was looking for a layer of dunlop with ILD 25-30, would you be comfortable purchasing the 4.75 ft/lb product? I realize this is all part of the risk of trying to build my own mattress, and I must make that decision myself, but part of my “research” is asking a more knowledgeable person what their risk assessment would be. 
If I apply these theories to the other dunlop products at the same vendors, I could purchase the following:
Queen 3" Talalux ILD 22 - SleepEZ $450 shipped
Queen 3" 4.75 ft/lb dunlop - Sleepwarehouse $332 shipped
Queen 3" 5.9 ft/lb dunlop - Sleepwarehouse $386 shipped
Queen 9" zippered cotton/wool mattress cover - Mattresses.net $207 shipped
Total = $1375 (possibly cheaper because I may be able to find that Talalux layer cheaper somewhere else, still confirming some things)
For comparison, that’s almost $400 savings over the SleepEZ 10000. Even if I got a layer wrong and had to buy another layer without any refund on the “wrong” one, I’m breaking even or better compared to the SleepEZ 10000. The comparable mattress at The Natural Mattress Store would cost me about $1700 more, so that is a no brainer.
Thoughts?