It took me a little bit but I got the Dark UFOs where I want them last night. New version is up on the MODsite.
I managed to make an addition to UFOL83 with volutar's MCDEdit program, which effectively blacks out the N/E diagonal walls in these ships. In celebratory fashion, I used them to darken Supply Ships too. I also changed Abductors to better suit my needs, their hard angles were the bane of my efforts. I call them Dark Abductors now and they look a little different, but layouts were left alone. (One side effect of my changes is that there are no more weird black triangles inside the Dark Abductors.) ALL silhouettes are now covered. I also found the missing file civilian mentioned and fixed a few bugs.
Now that those walls are no longer an issue for me, I can finally, maybe, begin work on making some Battleship variants. I've got some ideas...
And Louis: I plan to update both versions when I have some new maps.