Nice image Rex!
One strategy to improve the appearance of the stars is to use a Masked Stretch in Pixinsight instead of stretching the image with HistogramTransformation. Find the darkest part of your image and select that as a preview (I would often use a preview box about 20x20 pixels - it doesn't need to be large). Then use this preview as the background sample in the MaskedStretch process.
The effect of the MaskedStretch is to stretch the nebulosity without overly stretching the stars. This reduces the star size in the final image which lessens the impact (to a degree) of funky star shapes caused by optical issues such as tilt.
You can also use a star mask (masking everything except the stars), and then use MorphologicalTransformation in 'erosion' mode to reduce the size of the stars. Dont over do it here. try increments of say 25%.
I would be tempted to probably back off your noise reduction as well. I reckon there is some extra detail in there that you're missing due to the noise reduction step.
These are just small things, as that's a good image. In fact i'd call that a graduation from "Beginners Astrophotography" into the main game
