Hi Jeff,
Not much help with calibrating LRGB images, but yes you stack all your channels separately then make up your color image from there.
Colors look pretty good as well as guiding but one thing I have noticed is that the histogram is black clipped so you probably have captured more fainter details but that it has been lost somewhere along the line....
I`m sure if you redo it more carefully you should be able to bring out much more!
By the way what are the details for the exposures?
cheers Gary