Your setup sounds pretty similar to what I used to capture my M81 image. The f/5.5 focal reducer was an old Lumicon telecompressor. It would make that imaging train about 30% faster than your f/6.3; so, all things being equal, I'd have a better SNR than you. However, I can assure you that your T3 is substantially less noisy than my old 20Da. As such, I would say there's generally good reason to expect your SNR to be better than mine. Again - all things being equal.
That having been said, I have a feeling that our skies aren't equal. Do you know how dark your skies are? For me, I'm imaging from a blue/green zone (typically Bortle 4 - SQM 21.2 - 21.5). If your skies are significantly more light polluted, that's going to have a huge impact on SNR.
I gave a try at processing your data
. I posted my .psd files
(91MB) as well in case you want to look at them. This was a straight RGB processing (not a DSLR-LLRGB method of processing). My processing wasn't terribly careful - your image looks better to me (in terms of detail, etc.). I was mostly trying to bring the image to the point that I could look at the color issue.
It was rather a challenge - especially trying to pull out some blue. The first thing I had trouble with is that it was saved as a 32 bit tiff. While there's nothing wrong with that (presumably there's something good about it), I had to convert it in Photoshop to a 16 bit Tiff. When I did that, Photoshop wanted to do an HDR Toning to it. I've used HDR Toning, but only to enhance images that are well along the way in terms of stretching and detail enhancement. So, I'm not sure if I did any damage to the data while doing the 32 bit to 16 bit conversion. My gut is that I did not hurt it, but I really can't be sure.
The image had a significant gradient, as it was much brighter on the left side. Gradient Xterminator worked well to eliminate the gradient.
As you mentioned, you had some vertical banding in the image. Carboni's Vertical Banding Noise Reduction handled that problem quite well. But, after that, I was left with a circular gradient. I was able to eliminate this using an artificial flat.
At this point, I was ready to increase saturation. When I did so, I found a lot of red coming out, but no blue. This is very similar to the image you posted. To offset this, I pushed a little bit of blue into the galaxy with a slight blue curve, and then proceeded to do saturation adjustments using a variety of techniques.
I'm not terribly pleased with the result, particularly since I had to push some blue into the image. I have used color curves to enhance the color in images, but I usually don't have to push color into an image where its not there. I have my suspicions as to what may be the trouble here, but I'd be interested to hear your answers to my above questions (re:LP, modding, and CWB) before I throw out my speculations.