Hi litesleeper,
There are a couple of variables and unknowns at work here so I’ll share some thoughts and ask a few questions that may help nail down the next step.
It seems to me that the thickness of the comfort layer is likely the issue because you have a 3" layer of soft latex over a core layer of firmer latex and it seems likely to me that you are “going through” the top layer and “hitting” the firmer layer below. Normally the shoulders are both wider and lighter than the pelvis so they need enough thickness to sink in far enough until the torso comes into contact with the mattress and takes up the weight.
If you were to only go softer and not thicker and you are already going through the 3" latex top layer … you may actually feel the firmer layer below even more (you will “go through” it more easily).
So I have a couple of questions …
Does it feel like you are coming into contact with a firm layer below (you can “feel” the transition from soft to firm on your side especially)?
Is the overall “softness” of the comfort layer OK for you in terms of its “feel” and it’s just that the shoulders are sort of “bottoming out” on the layer below?
If you are OK with the overall softness but just need a little extra thickness to sink into … then a middle transition layer would work well (2-3"). This would be a less risky way to go in terms of alignment because the upper layers would be firmer. This is also assuming that the latex core is quite firm (which is very likely)
If on the other hand you want more surface softness and don’t just want more thickness to sink into (adjusting both the softness and the thickness of the surface layers) … then a couple of inches of softer latex on top would be the way I would go. This would be a little “riskier” because you would have 5" of soft latex on top which would have more risk of creating an alignment issue (sinking in too far with the hips/pelvis relative to the shoulders). It would be closer to the softness of the original foam (which was probably softer) and more “cushy” but a more risky construction.
A third option would be something like the Seven Comforts topper. My guess would be that it could work well. Being shredded (actually they are “microrods”) … it will allow the more pointy shoulders to go through it (displacing the latex to some degree) but at the same time will take up weight when the greater surface area of the torso comes into contact with it and it will also hold up the wider surface area of the hips/pelvis well. A design like this can be a good way to add softness/thickness and more localized relief and can provide a good combination of extra thickness and pressure relief, but with less risk to alignment.
They used to have these on Amazon for less but at the moment only the queen size is available there. but even at their main site they are very good value IMO.
Edit: see post #52 here first if you are considering ordering this topper.
Phoenix