Hi mg517,
Dunlop has a higher support factor than Talalay (it gets firmer faster when you sink deeper) and it has a more solid less “lively” feel than Talalay and there are many people who prefer it. My daughter also tried both and also prefers Dunlop over Talalay (she has an all Dunlop mattress). There is no “better or worse” here but just a matter of preference and which one seems to work best for the needs and preferences of different people. There are also many people who like a Dunlop support core with Talalay in the comfort layers.
I would keep in mind that primary support generally comes more from the deeper layers of the mattress not from the top layers which has more to do with secondary support (filling in the gaps) and pressure relief and that Dunlop is generally firmer than the same ILD in Talalay. It could be that with your lighter weight you may need a thinner comfort layer over the firmer support core to keep you closer to the support layers and create a more “stable” feel (less soft foam to sink into). The thickness of the layers often has as much to do with success as the ILD of the layers. I do know that the people at Clean Bedroom are generally very knowledgeable about their products.
With Dunlop you may be able to “get away” with the same 3" because of its higher support factor and because it has a more solid “feel” but you would still have the same support layer underneath you (your 36 ILD mattress and any other quilting layers that it has) and you may have some trouble sinking in enough with your shoulders because of the greater firmness as you sink in deeper with Dunlop. In a mattress that uses both types of latex … Dunlop is typically used for support underneath softer Talalay rather than the other way around but there are no “rules” that say it has to be this way. I would also keep in mind that all the layers of your mattress interact together so what is under a topper will also have an effect on how the topper feels and performs. All of this is as much of an art as a science.
Of course all of this is speculation because there is no formula that can predict individual experience and no matter what most people may feel “on average” on any combination, the only real way to know how it will work for you is through your own personal experience. Your best odds would be to try and match the ILD range (or the density) and design of the Dunlop mattress you tested and liked as much as is possible with the options you have available (I don’t know the specifics of the mattress you tested). Based on your feedback and apparent preferences though your plan would certainly be worth a try as long as the Dunlop was soft enough. Post #4 here includes some good sources for Dunlop latex layers or toppers.
Phoenix