Hi lesibly,
All the different factors in a mattress’ design will make a difference and they all work together to provide what I call PPP (Posture and alignment, Pressure relief, and Personal preferences). These include the type of material (or latex), the ILD of each layer, the thickness of each layer, and the type of cover that it uses among others (see post #2 here). All of these work together and every layer will have an effect on how all the other layers and components in a mattress interact together and with each individual person.
There is more information in post #14 here about the effect of layer thickness and the thickness of a latex mattress.
If you can’t test a mattress in person then your best odds of choosing the most appropriate layer combinations are with a more detailed conversation with a knowledgeable and experienced manufacturer or retailer who will know more about the specific mattresses they sell and how all their layers and components interact with different body types, sleeping styles, and personal preferences than anyone else (see mattress firmness/comfort levels in post #2 here).
In the end … the thickness or layering and design of a latex mattress or the options available before or after a purchase that is “best” for any particular person is the one that is the best “match” for them in terms of PPP and their personal value equation.
Phoenix