you have some nice data there but I can tell you that it is a mistake to use Halpha for luminance. It will attenuate the non-Hydrogen emission data, such as oxygen and sulfur and will therefore foul your color balance.
it is even a bigger mistake to use it for luminance for a tricolor emission line image.
if you take the time to think about what you are doing in technical terms perhaps you will understand.
here's a brief set of slides that illustrate graphically how Ha luminance skews color balance in emission line images but it does the same thing for RGB
http://www.narrowbandimaging.com/why...nance_page.htm