Hi Diane37,
Pure Latex Bliss has one like this with 4" of latex on top and while I don’t know the specific ILD of the latex … it would likely be much firmer than 14 ILD and closer to a support layer firmness.
I think that’s probably a good idea.
I don’t know how Mountaintop’s ILD’s compare to other types of latex (they use a different method of testing ILD than either Talalay or most other Dunlop). If you were considering softer Talalay for “feel” I would use something on the softer end of the ILD range … probably in the 14 - 19 range. If you are considering Dunlop and since Dunlop ILD’s are all over the map, I would make a choice based on a conversation with the supplier about how soft their Dunlop is relative to other types of latex … assuming they can make an accurate comparison based on their own knowledge and experience. You can get some sense of the relative ILD ranges for Dunlop vs density for 100% natural Dunlop which is made in a mold in post #2 here but when you are dealing with blended Dunlop then the density/ILD comparisons are no longer relevant because it depends on the blend so you would be dependent on the knowledge and experience of the supplier and their ability to compare what they have to other types of latex.
I would personally tend towards a shredded latex or lanoodles topper as a “feel” layer although of course all of this is so subjective that what works well for one person may not work nearly as well or “feel” nearly as good to another.
Phoenix