The Andromeda I posted was, as said, one of my older ones. I've since paid more attention to removing the blue hue. That shot was more to show the 135L and red halo around brighter stars which hinders its use if you want to do multiple colour channels at once.
Since I didn't mention it, that was at 1 minute exposures. That does need tracking, and I used the Astrortac at the time. I don't have notes on the ISO used but I normally leave it pretty high, either 1600 or 3200. For sure, once you can get a bit of exposure time thrown at it, it helps a lot with getting the dark stuff out. Then repeat the exposures as much as you can to get the noise down.
I played with DSS early on, but never really got on with it. I've gone to PixInsight but it isn't cheap and has more of a learning curve to it.
Here's a more recent attack on it. 450D with all filters removed. Astronomik CLS-CCD. Sigma 120-300 f/2.8 OS EX at 300mm f/2.8. 2 minute exposures. Note the stars don't suffer the red glow the 1235L does.
Due to the light pollution where I live, I can't do really long exposures even with filters. I can perhaps get 4 minutes usefully with a narrowband filter at f/2.8, after which I'm just picking up the noise floor.
If I stop being lazy, I really want to have a go with the Rosette nebula with the 300/2.8. I've only tried that with the 135L in the past and it is rather small in it.