DIY Mattress design theories - when to put a firm layer on top of soft layer?

It’s been over six months since my last post here.

Over the entire month of December through beginning of January, my husband and I tested out different configurations of latex layers. None of them worked well enough for us! I got so frustrated that we returned almost all the layers we’d purchased, packed up our testing bedframe into the closet, and I haven’t been able to revisit our DIY mattress project until now.

Looking at my notes for what we tested, we talked about variations of the usual progressive design, for instance:
Top 2" N3 Talalay, Middle 3" 75kg/m3, Bottom 3" 95kg/m3
It turned out that such a hard bottom core layer was problematic for us so we had to start over with our design plan. But nothing felt right until one night I decided to put one of our potential core 3" layers on top. It turned out to be the least bad of configurations:
Top 3" 75kg/m3, Middle 3" 65kg/m3, Bottom 3" 80kg/m3
This is why I’m now continuing this thread where we’d discussed the theory of putting a firmer layer on top of a softer layer.

I need help brainstorming testing options. I feel very confused now about what might work. Here’s a list of what we tested and the result. For simplicity I’m using density#s in kg/m3 and there was one Talalay layer we had to work with that I labeled N3 (the Latex Intl firmness designation for approx medium). Our original plan was an 8" mattress design with two 3" layers as the core, plus a 2" comfort layer.

  • 2" N3, 75, 85 = Too hard, lower back pain no lumbar support
  • 2" N3, 75, 80 = Too mushy/quicksand feeling
  • 2" 65, 75, 80 = Hip flexor soreness similar to when sitting too long, too soft?
    [li]2" 65, 65, 75 = Too mushy/quicksand feeling[/li][/ul]
    Gave up on progressive design
  • 3" 75, 65, 80 = Slightly too hard, lower back pain no lumbar support + husband had neck/shoulder soreness; but this is very close
  • 2" N3, 65, 80 = Hip flexor soreness similar to when sitting too long, too soft?

Typing this out I’m remembering that I had an idea to try 2" of 75kg/m3 with 1" of N2 Talalay on top to see if that helped fill in that lumbar gap. I also remember wondering if our planned wool mattress protector (St Dormier) would be enough cushion to provide the needed lumbar support. I didn’t order the protector yet. Could 1" of cushioning (Talalay or wool) even help enough with lumbar support? I know some vendors don’t even sell 1" toppers because they believe it doesn’t do much for you if you have less than 2".

I feel very torn about Talalay vs Dunlop on top because I love the feeling of how Talalay relieves pressure but at the same time think that it contributes to that dreaded quicksand feeling and having a hard time changing positions. I thought that the N3 Talalay would have a very similar firmness to the 75kg/m3 Dunlop, so it was surprising to me that it seemed to be too soft when the 75 Dunlop seemed too hard. Am I correct in thinking that if I’m waking up with hip flexor soreness that means my hips are sinking in too far so my body is no longer lying straight but is instead in a slightly bent/seated position? Do I need to move up to a N4 Talalay firmness?

Then for Dunlop there is one density I haven’t tested and that’s the 70kg/m3. I also considered going up to a 10" mattress design by doing the 6" core plus two 2" layers on top, which opens up a giant can of worms as far as possibilities. Sigh.

Anyway, like I said earlier, I am quite confused.

As an aside, but related question, I’ve found a lot of places who sell Dunlop toppers that can be returned, but I can’t seem to find many places who sell Talalay toppers that can be returned. Also, many companies have a policy where a customer can only return one item every twelve months, so I don’t think I can order any more latex to try out from any of the places I ordered before. (Rules out SleepEZ, SleepOnLatex, LatexMattressFactory) Any suggestions for somewhere else that allows returns of toppers and carries Talalay toppers?