Hi soxfan,
Your question is a complex one because the thickness and softness of a topper that is most suitable for any person on a specific mattress depends on their body type, sleeping positions, preferences, and sensitivities. In addition to this a topper and the mattress interact together and every layer and component of a sleeping system will have some effect on every other layer in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences).
Taken all together … this means that buying a topper that you can’t test in person on top of a specific mattress can be almost as difficult as buying a mattress because of all the variables involved and can sometimes take some trial and error.
Tufting in general will pre-compress the material which will make it a little firmer than the same material that isn’t tufted. It also can prevent the wool from shifting. Using wool over latex will also affect the “feel” and performance of the latex and would also be a personal preference. Some people will also just buy a latex topper and then add a wool topper to go over this rather than use a topper that has wool in the topper itself. There is more about the effects of a wool layer on the foam underneath it in post #6 here.
If the latex in your topper is the same type and blend as your old topper (which it likely is) and the wool is also the same then the quality of the materials in the topper would also be the same but the design has changed which means that it would be more suitable for some people and less suitable for others on the same mattress.
This is very possible and is the first thing I would consider. It’s not uncommon at all that a change in sleeping surface needs a change in your pillow, The choice of a pillow can make a significant difference in the pressure points on your mattress (in the upper body and shoulders in particular) and on the alignment of your spine (neck and upper body in particular). A pillow needs to fill in the gap between your mattress and head and keep your upper spine in its neutral alignment. Side sleepers generally need thicker firmer pillows, Stomach sleepers generally need softer thinner pillows (or no pillow at all) and back sleepers are somewhere in between. There is more about pillows in the pillow thread here.
When you add a topper to a mattress you are really adding a comfort layer over the mattress instead of having it inside the mattress cover itself. The odds are very high that your base mattress is still in good condition so it’s a matter of choosing a topper to go on top of it that is the best match in terms of PPP for that mattress and your body type and sleeping positions.
There is more information in post #2 herepost #8 here about some of the more common “symptoms” that people experience on a mattress and some of the possible causes behind them. There are also some “subjective” guidelines that can help you choose the most suitable topper in . There is also more in post #4 here about the relationship between primary support, secondary support, and pressure relief. The goal of a sleeping system (either a mattress or a mattress / topper combination) is to balance primary support which is mainly from the firmness of the deeper layers with secondary support and pressure relief which is mostly about the thickness and softness of the upper layers of the mattress. Too much or too little of any of these is what leads to the various pressure or alignment symptoms that people experience on a mattress.
While I don’t know the specifics of your mattress, your topper, your body type, or your sleeping positions and there too many unknowns and variables to use a specific “formula” to choose a topper … hopefully this can give you some insights into the possible underlying causes behind your symptoms and can help you with the detective work that is often necessary so you can choose a topper that works better for you.
I would also be aware that there may be other potential sources of your upper back pain if a new symptom appears suddenly after a month of sleeping on the combination because it may not be connected to your mattress / topper combination.
In many cases … because it can take some trial and error … the return or exchange policies for a topper can be one of the more important parts of a topper purchase if you can’t test the specific combination in person.
Phoenix
