Thank you Rick, as Stuart has pointed out, there is huge difference in star size between NB and RRB. I have added 3 hours worth of Ha data into existing LRGB, the Nebula signal is much stronger and stars appeared smaller, however in my opinion the star hue and softness look better in LRGB.
Please click link to see HaLRGB (7 hours):
http://www.astrobin.com/full/76369/0/
Regards
David