Hi Toro,
Trying to match one mattress to another in terms of “equivalence” is an exercise in imagination and educated intuition.
It’s made more difficult because your weight, sleeping position, and weight distribution and body type will affect how deeply you sink into a mattress with different parts of your body and will also have a significant effect on how much of each layer you will “feel”.
In addition to that there are different types of softness and firmness that different people are more or less sensitive to (see post #15 here).
Having said all that … if I had to guess I would say that a slightly firmer top layer (around 22 - 24) may feel closer “on average” and your proposed layering may feel softer than the one you tested.
I would also consider that the softer support core may also have an effect on your alignment vs a firmer support core depending on all the variables I mentioned (especially weight and weight distribution) and it’s more difficult to “feel” alignment … except when you wake up in the morning and experience back pain or discomfort.
As you also mentioned … the mattress cover can also have a significant effect on how the mattress feels … much more than most people may realize.
Phoenix