Hi TossingNTurning,
It’s not clear from your description whether you are having any actual “symptoms” from your mattress (such as back pain) or if you are just trying to change the more subjective “feel” of the mattress or the “sensations” you experience (see post #6 here).
If you are having actual symptoms then there is more detailed information about the most common symptoms that people may experience when they sleep on a mattress and the most likely (although not the only) reasons for them in post #2 here.
There is also more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may also be helpful in clarifying the difference between “support” and “pressure relief” and “feel”.
These posts are the “tools” that can help with the analysis, detective work, or trial and error that may be necessary to help you learn your body’s language and “translate” what your body is trying to tell you so you can make the types of changes that have the best chance of reducing or eliminating any “symptoms” you are experiencing.
The choice of materials is always a preference choice rather than a “better/worse” choice and like any material there are certainly people that don’t like the “feel” of latex and prefer other types of materials or mattresses.
If you are trying to firm up the “feel” of the top layers then changing the layers as you did (with the medium layer on top of the soft layer) would be the most common way to accomplish this.
If you want to firm up the support of the mattress but keep the softness of the sleeping surface then the most common way to do this would be to put the firm layer in the middle and the medium layer on the bottom.
If neither of these options is successful then you could also replace one of the layers with a layer that was firmer (such as replacing the soft layer with medium so from top to bottom you would have M/M/F).
I think that the most important goal of a mattress is that it “disappears” underneath you rather than “wows” you and that you wake up rested and refreshed without any pain or discomfort. When it comes to mattresses … feeling less (pain, discomfort, pressure points, or “annoyance” because of how the mattress responds or from waking up) is usually better than “feeling” more and the “wow factor” is usually more a part of the showroom feel than your actual sleeping experience since you can’t feel your mattress when you are asleep anyway.
A cover can certainly have a significant effect on the feel and performance of a mattress because all the layers and components of a mattress will have some effect on every other layer and component and the mattress “as a whole”. There is also more about quilted covers vs thinner unquilted covers that are more “stretchy” in post #12 here.
Having said that … it’s unlikely that you will find anyone that has tested the effect of the different covers that are listed on the specific latex layers you are using to compare them in person but even if someone had compared them in person their experience and perceptions and how they compare them may still be different from yours.
You are the only one that can feel what you feel on a mattress and there are too many unknowns, variables, and personal preferences involved to use a formula or for anyone to be able to predict or make a specific suggestion or recommendation about which mattress or combination of materials and components would be the best “match” for you in terms of PPP based on specs (either yours or a mattress) or “theory at a distance” that can possibly be more accurate than your own careful testing or personal sleeping experience (see mattress firmness/comfort levels in post #2 here).
When you can’t test a particular component such as a cover in person then the most reliable source of guidance is always a more detailed phone conversation with a knowledgeable and experienced retailer or manufacturer that has your best interests at heart who will know more about the specific components and covers they sell and are in the best position to compare them to other covers they are familiar with than anyone else.
It may also be worth removing the top of the cover and sleeping more directly on the latex itself (using the layer combination that works best for you with only your mattress protector and sheets on top of the latex) to give you a better sense if you would prefer a more “stretchy” cover that has less effect on the contouring of the latex.
The first step in any “fine tuning” process is identifying exactly what you are hoping to change (pressure relief, support/alignment, or “feel”).
Phoenix