Thanks for your help guys. Still battling this issue of the mottling. Not understanding why it is happening, I can't remedy it intelligently (not that I am a chemist) other than blind experimentation. Heh.

But I have confirmed it is happening during the B&W development stage.

I've added benzo, and bromide, tried development in Xtol, increased temperature and decreased development time. Nothing seems to have an effect on the mottling. Are these the dye clouds I am seeing giving this mottling?

I am convinced there is a specific cause and if areas do not have this mottling then it is possible to prevent the mottling from happening altogether.... PH? Different developers? Anyone have any ideas?

I know I could be more productive with my time then pissing around with this method of photography with color paper, but hell, it's keeping my brain active, and my hands busy.