Hi Pid.
I,m no expert but to me the data you have is very noisey and grainy.Also you have,nt quite got focus,the stars are a little bloated.
You have only taken 10 darks,but I would push for maybe up to 30 to get a good master dark.Another important calibration Frame is Flats.To me Flats are the most important of Calibration.
Were your darks taken at the same temperature as the lights,and for the same duration (240secs).
Regarding adding the Ha detail,i would apply it initially only to the RED channel of the RGB,theirfore avoiding the salmon colour effect.You can blend the Ha at 100% opacity,or better still maybe around 25-30% to avoid washing out the colours,and ending up with a dominant red.Although I often do end up with an overall red Nebulae.
Other people better qualified may chip in with this,so you would get better overall info.
But well done with what you have achieved here.
Mick.