Hi Clawdia,
The response time or resilience of a foam material has very little to do with the pressure on any particular area of your body which is determined by how well the material contours to the shape of your body and your weight distribution on the mattress along the surface area of your body. Memory foam (like latex) contours to the body shape very well which is why it relieves pressure (although some memory foam takes more time to soften and contour. For example … even a carved piece of wood can provide great pressure relief … until you move (see post #2 here).
Again … there is lots of misinformation all over the web that is meant to promote something that someone is selling and most of it talks about one material being “better” than another without talking about the tradeoffs involved. When your body is at rest and you and the mattress are in equilibrium … then there is no movement or “direction” of pressure … only the actual pressure itself on the body surface that is determined by the resistance of the foam under each part of your body and the weight of your body that is spread out over the surface area that is in contact with your body. The more surface area that is in contact with the mattress (determined by how well a material contours to your body shape) … the more your weight is distributed over the surface of the mattress.
If you decide to try the slow response latex then I would probably try the softest version because the firmer versions will probably feel firmer than most memory foam. As you can see here … it comes in ILD’s of 15, 21, and 27.
I know I’ve mentioned it before but considering your feedback and that a featherbed seems to work well for you I would probably consider a down alternative instead (purchased from a big box store so you can test it and return it if it doesn’t work for you) so that it’s not as costly to replace it when necessary and you would have the benefits of sleeping on something similar to what has worked for you.
Phoenix