Hi rockalicious2013,
You can read a little more about both here that is more “fact based” than much of the information on the internet which tends to promote one over the other and that has been sourced from a great deal of research and conversations with manufacturers that have worked with both for decades and I would rate Dunlop and Talalay roughly equal in terms of durability (bearing in mind that durability is also affected by softness so softer versions of both would be less durable than firmer versions). You can also see a video of a Dunlop mattress that was almost 50 years old in this article and there are many examples of both which have lasted decades (usually in firmer versions). In practical terms I would treat them as equals in terms of durability.
Dunlop is also denser and has a higher compression modulus (the rate that a material gets firmer as it compresses more) so it can “start off” softer than a Talalay layer of the same ILD with initial compression and then once it is past 25% compression (where ILD is tested) it would become firmer than Talalay (which is what you felt). This is why it is considered to feel firmer than Talalay because most people don’t sink into a layer exactly 25% and for the same reason is often considered to be more supportive even though the surface can feel softer. in other words it has a different response curve.
Dunlop is also less breathable than Talalay but it is more breathable than other foams and most people would not have an issue with heat with any latex (although this too will be affected by softness because you will sink in more with softer layers which puts more insulating foam around your body). There are also many other factors that are part of temperature regulation in a mattress that you can read about in post #2 here which can also make a significant difference.
I have certainly tested both fairly extensively although they were not the specific mattresses you mentioned they were similar in construction. I personally prefer Talalay but my daughter who has also tested both has a clear preference for Dunlop (which is what she sleeps on). It really is a matter of personal preference because as your testing indicated they both share certain properties of latex like high elasticity and resilience but they feel and respond quite differently. I think much of the “misinformation” on the internet tries to promote one over the other or present one as being “better” than another when in fact they are just different and the choice is a matter of personal preferences IMO.
Phoenix