Hi rob2121,
There is more about the different “symptoms” that people may experience on a mattress and some of the possible causes for them in post #2 here and the posts it links to. What you are describing would most likely be related to either the thickness/softness of the comfort layers or a pillow issue.
There is no specific firmness that is specific to 4 lb gel memory foams (or any memory foam) because any density can be made in a range of firmness levels (see post #9 here and post #8 here for more about the different properties of different memory foams) but a quilting layer or any layer or material over memory foam can certainly affect how it feels and performs because it will affect the amount of heat that reaches the memory foam and will also add its own properties to the comfort layers. Thicker layers over memory foam will have more effect on it than thinner layers. For some people these types of combination would be beneficial and for others it would be detrimental depending on their preferences.
Phoenix