Hi Dreamer77,
That’s good news and it would probably be worth sleeping on your upside down mattress for a few days to see how it feels over a little longer period of time. The 2" layer of softer latex on the bottom would provide some additional flex and softness to the mattress but having the firmer latex on the top would also provide a more “on the mattress” feel that you seem to like.
If your mattress has loose layers with a zip cover then it may also be worth trying just the 6" latex core to see how it compares and a firmer top 2" layer on the same core may also be worthwhile considering (although I’m guessing from your comments that it doesn’t have a zip cover with layers that can be removed). Of course it’s also possible to remove the 2" layer even if it’s glued but it can be a little tricky.
That’s certainly possible and your experience, at least for a single night, seems to point in that direction (although a few more nights experience would be a good idea).
It would probably rule out memory foam which is a more “in the mattress” material but it may not rule out firmer polyfoam which is a more resilient and “on the mattress” material than memory foam and your experience seems t0 indicate that it wouldn’t rule out firmer latex foam either which is an even more “on the mattress” material than polyfoam.
This would certainly be worth considering and as I mentioned I would tend to sleep on your upside down mattress for a few days to see if your experience is consistent and not just an anomaly. The single 6" core with a relatively thin and firm natural fiber or foam topper could also be worth considering.
The only way to know would be based on your own personal experience so I would make sure that if you purchase a topper that it includes a good exchange/return policy so that if it is too soft you can exchange it for something firmer.
If the bottom fabric is stiffer than the top sleeping surface then it would definitely have some effect on the ability of the latex underneath it to contour to the shape of your body and would feel firmer.
You can also buy a new cover if you decide to keep the latex layers (or at least the 6" core) inside your mattress.
Based on your experience and lack of back pain it’s quitepossible that you may not need zoned latex but whether to buy a new mattress completely or a mattress/topper combination is a choice that only you can make based on your your personal testing experience and your willingness to experiment with toppers on a firmer mattress (if you even need one which you may not). If you do decide to go in the direction of a mattress/topper combination then post #2 here and the topper guidelines it links to that can help you use your sleeping experience as a reference point and guideline to help you choose the type, thickness, and firmness for a topper that has the least possible risk and the best chance for success. It also includes a link to a list of some of the better online sources for toppers I’m aware of as well although Beloit may also have some toppers available as well.
I personally would be hesitant to sell the latex mattress at a significant loss unless you are confident that there really isn’t a combination of layers and materials that uses the 6" core that would work well for you.
Phoenix