Hi scottod17,
The thickness of a mattress and the number of layers it contains are just some of the many criteria that will affect which mattress is the best match for you in terms of PPP.
For most people … and depending to some degree on weight … somewhere between 6" and 12" of latex would generally be in the range that most people would choose although any thickness or design may be a preference for some people. There is more about the effects of thickness in post #14 here and more about more vs less layers in post #2 here but in most cases when you can’t test a mattress in person then it’s usually best to make these types of choices based on a more detailed conversation with an online manufacturer or retailer you are considering because they will be more familiar with “matching” their mattresses to different types of people and preferences and be the best source of guidance about the options they have available than anyone else.
Phoenix