Hi d3adrock,
Unfortunately there is no way for me to know which combination of layers you will do best on based on specs (yours or a mattress) or “theory at a distance” that can possibly be more reliable than your own personal sleeping experience.
Having said that … I would tend to prioritize support/alignment which is the single most important factor in your body’s ability to rest and recover over the course of the night. The next most important factor would be pressure relief and the least important factor would be the more subjective “feel” of a mattress.
All of the options you are considering would result in a softer mattress (to different degrees) but I would be cautious about making changes that are too big and may “jump over” the layering combination that is the most suitable for you because it seems like the combination you have now is very close to being a good “match” for you in terms of PPP (Posture and alignment, Pressure relief, and your Personal preferences).
The suggestions that they are providing come from many years of experience based on the “averages” of their customers that are similar to you although of course not everyone fits inside the averages of other people. I would also keep in mind that what you may “think you need” based on more subjective assessments of “comfort” or “feel” alone may be different from what your body actually needs.
While I can’t tell you what you “should do” because this will really be a matter of “informed best judgement” … I would keep in mind that based on “averages” having two soft layers would be a more risky choice both in terms of having suitable support/alignment and in terms of durability as well (thicker layers of softer materials will be less durable than firmer layers of the same material).
If your mattress is a little bit too firm then some of the suggestions in post #2 here may be helpful as well.
Phoenix