YES! I was hoping for this one as soon as I saw the update notification for this thread. Great job, GigaLem and Plom!
Due to the terrain shape of the specific level above, it looks a bit more like snow than clouds in this case. But since all the terrain pieces are still the same, i.e. cloud shaped, I think if you create a less "mountain-like" structure out of those pieces, it's going to trigger the association "Sky" again right away.
Now I'm actualy thinking about using this tileset for at least some of the Sky levels from Lemmings World Tour once I convert it to New Formats. I know Flopsy did that for most of the Desert levels from SEB Lems.
However, if I want to keep both Sky tilesets available in the editor, I guess I have to backup my old translation table for Sky and then create a second one that replaces all old Sky pieces with the new ones? Then insert the new translation table into the respective folder while converting all Sky levels I want to have in the new tileset, then replace the translation table with the old one for all levels I want to keep the old Sky tileset.
Correct, @namida / @Nepster?