I've shot this once before, for a total of 2 hours, under Bortle 7 with a color camera.  

I'd like to try again with a monochrome camera, Bortle 2 and up to 50 hours of exposure time.  

Is there anything particular to this galactic cluster, i.e. blowing out the cores when shooting in luminance–that might help me to get a better image?

Jerry