Hi Mightyman,
I think post #7 here has the information you are looking for although describing “feel” is as difficult as describing the taste of a food that someone hasn’t tried before and the best way to know the differences between them would be based on your actual testing or experience.
There are many firmness levels of latex (probably more now than there was then) so I don’t know which firmness level would be closest to the mattress you used to sleep on and any differences in weight and body shape would also change the feel and performance of a mattress in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences) because the same firmness level will generally feel softer for someone that weighs more than it would for someone who weighs less. There are quite a number of Dunlop latex mattresses that use 6" of 100% natural Dunlop latex though (including some of the manufacturers that are included in the list of online members that are linked in the tutorial post) and diynaturalbedding is a local option that would also be worth considering because they would also have a mattress with 6" of Dunlop latex (in two 3" layers) so you could try different combinations to see which one was closest to what you remember. If the firmness level of the two 3" layers was the same and the cover was also similar then the mattress itself would be very similar to the mattress you are describing even though it may feel different now than what you remember.
Phoenix