Hi Gardenguy,
Let me give some suggestions for your questions, not sure there are any exact answers because of a number of factors.
Regarding the HD and the HR, it is difficult to make a specific answer as it depends on how all the layers work together, how the mfgr’s are measuring the ILD/IFD, the formulations, and the particular density of each piece of foam. There are no set answers, it really has to be tested by yourself or other individuals. Most people would first only make one ILD range adjustment to compare HD and HR support comparisons.
Regarding 36 Natural vs Blended:
Being different formulations and different densities they never feel identical, and it may be the case that blended is “slightly” less supportive, but depending on the what layers are used on top of these cores, I would say the support difference would be negligible. A good summary of the differences is located in this post.
Regarding matching HR 34 HR and Latex ILD:
This type of comparison is really difficult to make, not knowing enough about the foam, as I mentioned earlier, as so many companies measure ILD differently and it’s not the only way to measure “support”. I certainly would always tell people to use a 36 or 40 ILD as 6" latex support cores, but whether they replicate a poly core is a more complicated question. More information can be found in this here.
Whether or not Dunlop is “superior” in support is probably a little strong, as you noted both are mid 30’s ILD, I assume you are talking about high quality latex manufacturers, these will both be very very supportive, and calling out one as “superior” to the other is a bit dramatic in my humble opnion. More important form many consuemrs will be how price plays a role in this decsion. Of course we have some great content on this subject as noted in this post.