Looks pretty good. Seems a bit dark. The RASA is a FAST scope, with big aperture, so signal should be very strong, especially with 8.4 hours of exposure time maybe its the LP you mention? That always plays havoc with me. Did you use noise control in the galaxy? It looks as though you did, and if so, I would say maybe a touch too much. If not, then its something else. Careful not to clip the low end (maybe why its a bit dark?) Space is not black. If you make a star mask and expose only the stars you can bump up their saturation and get nicely colored stars. I just realized that the focal length you using is small for the aperture, so the scale is not typical for galaxy hunting. is this a crop? That might explain things.
Great effort. Keep at it. I find the smallest changes in the settings critical in Pixinsight. An image can be transformed with the smallest setting manipulation. The devil is in the details as they say.
Rodd