I didn't use flats, darks, or bias data. I've got the camera pushed very close the rear plate on the scope to minimize vingetting. I've taken flat data with the 6D and frankly over everything but the extreme corners, it's fairly uniform. I'm not saying that flat data won't improve the image (it will); but, in my case, it's not a major issue. This data was taken on an evening with an OAT of about 65 degrees so it wasn't cold, yet the 6D performed quite well with respect to noise. Even when I do a really hard stretch on the subs, I don't see a lot of fixed pattern noise so darks won't do much either.
Now, when it comes to dithering, there's a story. First, I took this data over two night--mainly because I can only get about 1-1.5 hours on this object while it's high enough above the southern horizon. I wasn't successful at lining things up perfectly between the two night (close but not perfect) so that dithered the two sets of data. Second, I am battling a strange phenomenon that I haven't quite figured out. If I look at each of my 3-minute subs, the stars are pretty close to pinpoint round and yet if I rapidly scroll through my whole set of subs, the image walks across the sensor. I only pause for about 2 seconds between the subs so I am completely baffled as to why I can have sharp star images and still have image walk. It is exactly what you want for dithering…but I'm not doing it! Whoa. I've measured the walk and computed how out of round the stars should appear and (at least on the one data set I measured) it doesn't jive. The stars should be slightly oblong. I'm still scratching my head over what in the world could be causing the scope, the sensor, the optics, or anything else to shift a little between each two second frame. I'll have to go back and look at the camera for this data set to see how much the set moved but I bet it did. I've been pondering making a post about this but I really don't have my ducks in enough of a row with data and such to have a controlled discussion about this one yet. But, since you asked, yes…I am dithering; but not exactly intentionally. This may be something as simple as "mirror flop" or flexure but it's hard to isolate. This is another reason that an OAG would almost certainly help. I'll post the solution, the problem, or both if I ever make any more progress on it. In the meantime, I'm happy enough if I can keep getting results like this one.
As for processing, yes there was a fair amount on this image; mainly because of the color palette.
My advice is too keep it as simple as possible when you start and to work your way up as you get things working. Just start with lights and get your processing figured out first. You should be able to get some very nice results. Flats, darks, etc can then be added to make things better and to fix specific problems. AP is definitely and exercise in divide and conquer as you work your way up.