Hi Ho,
There is more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may be helpful in clarifying the differences between firmness and “support” and “pressure relief” and “feel”.
Dunlop has a higher compression modulus than Talalay (compression modulus is how quickly a material gets firmer as you sink into it more deeply) which means that if you had a layer of each that were the same thickness and ILD in the top layer of a mattress and were sleeping on them directly that for most people the Dunlop would “feel” firmer than the Talalay. This is something that you would notice more in a top layer than the deeper layers but the type of latex in a mattress is a preference choice and not a “better/worse” choice and either type of latex can be a perfectly suitable choice in any layer of a mattress both in terms of comfort and support in a suitable firmness level. I don’t know of any reason that I would want to add another layer of Dunlop (or Talalay for that matter) to your mattress and I would focus more on making any changes to your vZone (which is 3" not 2") or the other layers in your mattress that would resolve any comfort/pressure relief or support/alignment issues you may be having rather than adding any additional layers.
One of the main benefits of your mattress is that both the layering and the zoning can be changed so that the mattress can be “fine tuned” in many ways and the first thing I would do is talk with Flobeds about your experience and any actual “symptoms” you are having when you sleep on your mattress so they can provide you with the help and guidance you will need to make the type of changes to your mattress layering and/or zoning that you are looking for.
Phoenix