Thanks for your kind comments. Most articles I have read on adding Ha data to RGB seem to be based on mono chips. I tried adding the Ha as a BW to the red channel in RGB but ended up with weird star colors. In this image I think I ended up leaving the Ha as a red image and adding it to the RGB using the screen function in layers pallette. I think I over processed the image trying to get the faint detail making it a bit grainy. I had and extra hour of Ha data but it was lost when my laptop hard drive died.
Anyway, thanks for the comments, I might try reprocessing this image with some of your ideas.
Clear skies
Ken