Honestly what I was looking for is someone who has tried the crossing. I would like to know some breeder input as some in other breeds say breeding mottle carrying blacks to mottles produce the best color. I am wondering if multiple generations of mottles to mottles have caused some coloring issues for people. There are some mottles out there that I have seen with good SOP coloring, and I am wondering if they are using any black mottled carriers. I assume they are being picky about coloring and culling as well.
There is a way a gene interacts on paper and then they way breeders "anecdotally" experience them. Both insights are useful. Breeders of horses that come in grey and black won't breed grey to grey to grey for multiple generations on end as it will create colors that wash out easily. Breeders of roan and red cattle won't breed roan to roan for generations on end either. I am curious if there are is a similarity in this with Javas. Clearly color isn't the easiest thing to breed for otherwise it wouldn't cause so much aggravation.
I would really head over to the Heritage Large Fowl thread for the info you're looking for. Most Java people on this thread are either just owners or casual breeders, or they just haven't had Javas long enough.
There are some members of the Java association that I electronically converse with, that are a bit more serious about keeping notes and we share info about things like colors, breeding, etc.