They are hard to reach by phone and didn’t answer about half my emails after purchase.
Their system for beds is to put a 2" 22 ILD layer over a 6" core. The core is what is “adjustable”, at either soft, medium, or firm.
As far as I can tell, they don’t have top layers of different firmness.
It’s not really feasible to exchange the core, (Imagine trying to ship back a giant floppy 6" slab) so you may as well consider yourself stuck with it.
You might end up like I did, where the top layer is too soft, and bits of the core are too hard, so that you can feel an abrupt transition. Or maybe the top layer is the wrong firmness for you anyway. Then you are screwed.
I should also mention that they have a 2+ week lead time.
The other mattress companies aren’t as good of a value, though.
For example, Brooklyn Bedding has the aloe alexis or bamboo bliss, but you’d also be paying for a little latex and a lot of cheaper poly foam. (I mean, maybe you won’t notice the difference anyway.) Their cover also has foam quilted into it, which you may or may not like. At least they have a good comfort exchange policy.
What I did was order from Arizona mattress company, and purposely ask for the cover to have an extra two inches of room, in case the top layer wasn’t right, and so I was prepared to either replace the layer (at my own cost) or stuff in more layers.
One more thing. Trying to determine what mattress firmness is best over the phone, even with a knowledgeable and overly friendly salesperson is going to be a crap shoot. You should try out some beds in person to see if you even like the feel. Then report back here any maybe Phoenix can give you some firmness suggestions.