Logan,
Unfortunately, the files presented are TIFF, which loses linearity fast (well, a lot faster than the raw FITS do). I had a VERY hard time stretching the red as well, and had to put them into CCDStack and use DDP, balanced with Gamma and Background, then restretched again with DDP rebalanced with Gamma and Background (2 in total I think).
Then adding in the H-alpha using an action by Annie (Annie's Astro Actions for PS) after also having stretched the H-alpha frame.
Balancing the blue in the colour was problematic actually, and you can see it in the end result. That's after a lot of blue curve fiddling, backgraound, midtone and highlight balancing etc etc.
There is also a registration misalignment with I think the H-a frame, so you need to run that through CCDStack or DSS to align with the others, then save that as a scaled image - its a fair bit off in rotation and you can still see a slanted line near the bottom of my image. Also remember to sharpen the H-a prior to stacking it - makes a HUGE difference.
It's nice data - Mark just needs to hand us the FITS for some real playing
(HINT HINT!)
Rick could have done it all in The Headache Machine...aka PixInsight