I went and reprocessed a bunch of M42 data back from when I had a VC200L (hence those diffraction spikes). I set the debayer WRONG, and it came out a horrid purple all over, and unfixable. Well, why not go grey scale, push it, tone it...
I kind of like it. Not bad for dud processed data, pushed to the extreme. Not that it matters, but it's about 45 minutes total, with an unmodded Canon 5D MkII.
Processed it through PI, with NO flats or darks - I couldn't find them!!! PI does such a fantastic stack routine, MUCH superior to DSS. Set the debayer to GRGB, which is obviously wrong. Then, I did a small ScreenTransfer stretch in PI, and did the rest in PS (I really don't like some of PI's routines still, but am learning them).
Thanks for the comments. I have even more crudy old data to at least "immortalise" in some way.