I'm using Ascension's Atlas style (in Photoshop CC), but I want a little extra. There's a portion of the map that I've created, but the "cartographers" of the fictional world have not yet discovered that portion. I thought that the best way to cover up that area would be to obscure it with clouds.

I tried using a fiber render rotated horizontal (and select color + fuzzy select + clear of course), but it doesn't look cloudlike enough. I tried using a normal cloud render, but it didn't convey "PARTS UNKNOWN" very well, and also was easily confusable with a mountainous area. I ended up going with the fibers superimposed on top of normal clouds using soft light mode, and it looks... eh... vaugely passable... but I was wondering if there are any more techniques I could try that might give a better result?

(Link to my map with the method I described above: Here)