Hi Catherine,
My “gut” tells me that you will likely be pretty close … even without zoning … but on the off chance you do need the zoning, you at least have the ILD’s you would need to make it effective. Things are looking hopeful, at least from my end … but then I’m the one theorizing and not sleeping on the mattress and we both probably know that experience trumps any theory (hedging on my own version of “famous last words” :)). I agree with you too about the feeling of memory foam although I would consider it in thin layers mixed in with latex if I had to.
I’m looking forward to your next report. In post #8 here there’s a few good resources on pillows although there’s lots more and pillows are probably even more “personal” than a mattress. I’d love to hear what you end up with here as well.
Hi Britanyy … and welcome
One of the difficulties that some people find with latex layering is the difference that layer thickness can make in how the layers interact and how “softness” is perceived so it would be helpful if I knew the layer thicknesses of your layers as well as your height/weight (as in my earlier comment to Catherine it always feels strange to ask people this but it really does make a difference). I’m assuming too that each layer is Talalay and that none of them are convoluted?
I’ll be happy to offer my 2 cents … but the extra info would certainly help 
Phoenix