A large proportion of people who tried this form of cross processing reported poor results with Fuji CA paper. That is about all I can say. My work was all with Endura. This process would not work for me at all with Supra I, II or III.
I saw some mottle with Endura. It was not a consistent problem though. I used to see it with Ektachrome paper as well. Some old notes say that it is typical of reversal color papers.