Hi relay700,
There will be a break in and adjustment period for any new mattress or sleeping system as the mattress loses any of it’s “false firmness” and the cover stretches and loosens a little and your body gets used to a mattress that is different from what it is used to sleeping on (see post #3 here).
I’m also not clear from your comments whether you are trying each layer separately or if you are sleeping on the combination of all three layers since your comments seem to be more about each layer individually and not the combination of all three. Each individual layer has a different function inside a mattress so assessing each layer by itself will have little to do with how the combination works together “as a whole”.
“Support” is also often misunderstood and many people believe incorrectly that “firmer is better” or “more supportive” or that one type of support system is “better” than another when the real goal of a “supportive” mattress is to keep the spine in good alignment and this requires the type of contouring support that allows some parts of the body to sink in more and some parts of the body to sink in less and this will vary on an individual basis. There is 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/alignment” and “comfort/pressure relief” and “feel” and how they interact together.
You also didn’t mention any of the specific symptoms you are experiencing when you sleep on your mattress because how a mattress feels and responds when you push on it with your hands or sit on the side is very different from how it will feel and respond when you sleep on it over the course of the night.
Your mattress (soft/medium/firm … hopefully with a suitable cover) is certainly inside the range that would work well for most people in your weight range but each person is unique and a mattress or a combination of layers that works well for one person or even for a larger group of people may be unsuitable for someone else to sleep on.
Based on your comments you already have a “proper support layer” (the firm) in addition to a transition layer (the medium) and a comfort layer (the soft) that would work well together for most people even though it may not be suitable for you (although you will need more time on all three layers inside a cover to know for certain). Both Dunlop and Talalay latex are made in 6" molds that aren’t two layers that are bonded together. There is also more about the pros and cons of a single 6" core vs two 3" layers in post #2 here.
Overall … I think that the “best” suggestion for now would be to put all three layers together with the firm on the bottom, the medium in the middle, and the soft on top inside your cover (assuming that you have a cover) and then sleep on it for a few weeks to see how it works out for you and whether you are experiencing any actual symptoms over the course of time.
Once you have a little bit more time on your current configuration then you can use any specific symptoms you experience on your mattress as a reference point and guideline to help you decide whether any changes will be necessary and if they are on the types of changes in your layering that may be most helpful.
I would also read the comments in the first part of post #2 here and the posts it links to about putting together a DIY mattress as well…
Phoenix