I bought a set of those bases I called it extra firm in my desc but guess its extra extra 
https://forum.mattressunderground.com/t/aloha-and-mahalos-we-finally-bought-a-custom-latex-bed
even have a pic of it with two 3 inch layers on there base
I like super firm bases and softer tops with some support wife and I both like that solid feeling rather than the sinky feeling of beds ? but this is like describing pizza or lasagna hard to describe
I can say this we liked it over the other ones we tried obviously cause we bought it
but we did try it with just one 3 inch layer and no way would I do that for me it was bottoming out to quick but a soft bottom out
two 2 inch were close in price so we just jumped to two 3 inch
also trying a standard bed they sell which is 9 inches latex and 1 inch wool or something like that the latex layers are a 6 inch base with a 28 or 19 top was nice but I found the 3 layer setup of the super firm sale bases has a nice sink in comfort top level feel and the support for me still is there and that super firm base kinda gives you a feel of no jiggle as my wife says as I say it stops you from sinking to deep into it I hate that banana feel of to soft beds that don’t have that support and only comfort layer
I think Phoenix wrote somewhere about 3 layers compared to two layers ? and not sure if the word is transition that 3 layers has or what the word was but they do seem to kinda work better both my wife and I are happy where some of the other thinner 2 layer beds kinda are to firm or two soft to quickly ? hard to describe for me
I guess trying a 3 layered bed with a 38 base layer (I keep forgetting if its 38 or 39) but going to the super firm did not make as much difference as I thought it would ?
again 3 layers
now a two layer 38 base and a 19 top or 28 top for me was easy to feell the difference !
where the 3 layers its harder to feel the differences but they are there just more subtle ?
and a two layer super firm base would just be to firm unless you went with two more layers a comfit layer and a extra base layer for support making that super firm more a super support layer
maybe the best way to describe it is a progressive curve ? not sure if you are into any kinda sport with suspension but its for sure like a progressive rate spring setup soft at first for the little bumps but the last bit firms up really quick to absorb the bigger bumps and you never feel bottomed out