I dont understand why you futsed with the stars. OIII stars are always bigger than Ha in NB (even with 3nm OIII), and anyway star colour is irrelevant in NB. Why didnt you just go with Ha stars only (as white) given they are smaller?. If you want proper star colour then do some short RGB exposures, extract the stars and insert, either as is, or as a colour channel for the Ha stars as lum.
Hi Fred
Futsing around with my data is what I do I had actually intended to grab some RGB for stars but clouds rolled in so I just worked with what I had
Next project I'll make sure I grab some RGB data too.
Thanks Adam, Nik, Greg, Steve, Mike and Stephane, and everyone thats been so generous with their comments! Huge surprise! I can't quite believe 15 months ago I was staring at my first star tracker and DSLR and wondering WTF with it all
Learned so much from these forums and youtube contributors. Its really amazing that we share so much info in the astrophotography community - I look forward to learning lots lots more!
I had actually intended to grab some RGB for stars but clouds rolled in so I just worked with what I had 
