Loving that data! I ended up doing a sigma reject, with a Catmul-Rom, and then a Sum-Median stack - all CCDStack of course.
Decided against colour (green... no thanks!), went grayscale.
LOTS and LOTS of detail! I had to upload as a jpeg - Astrobin is having an issue with png's at the moment. Hence some image artifact.
Lay off the fake diffraction spikes though David - the beauty of a 155mm AP refractor ruined with fake diffraction spikes
I dunno, never like seeing M42 "hanging" - I had to rotate it 180°
http://www.astrobin.com/full/63029/0/