Thank you kindly for your inquiries! Based on the information you have provided, I recommend a soft Talalay over medium Dunlop over firm Dunlop for your wife. At 170lbs, the soft Talalay latex will provide the contour and pressure relief she will need as a side sleeper, while the medium over firm layers below will provide gradual support. For your side I recommend a configuration of medium Talalay over medium Dunlop over firm Dunlop. At 200lbls, the medium Talalay will provide similar contour for you that a soft will for your wife at her weight.
Talalay latex is a slightly more open-celled foam compared to that of Dunlop, and therefore provides a softer/plusher feel, which is perfect for contour and pressure relief on a mattress surface. Dunlop latex is heavier/denser and therefore firmer compared to Talalay, and is ideal for support within a mattress.
The main difference between our Natural and Organic mattress models is that the Organic line consists of a Natural Talalay top layer, and GOLS Dunlop layers below, whereas the Natural line consists of all 100% Natural Dunlop and no Talalay latex. Both our Natural and Organic latex mattress lines are equally long-lasting due to the cell-structure in latex foam being made of natural rubber from a rubber tree.
This makes latex a very durable foam compared to that of other mattress foams in the industry.
I hope this information helps. Should you have more questions, please feel free to come back anytime, or call our office at 480-966-8731. Thanks again!