Yes, Joanna’s original suggestion from the first post in this topic, which is that control lines will get you a better result than the AI mask for complex sky selection.
You could also keep your AI sky mask and add a control line as a sub mask to grab the rest of those little pieces of sky that were missed.
… and for those on PL 10
Alternatively, you can now use the Control Brush. Select a color using the color picker, roughly paint over the desired area, and then adjust chroma and luma as you would with the Control Line.
Fine. That is about what I have experimentally concluded myself. Hope the future will be even better.
My 2c worth, use the tool that best fits the subject. Don’t use AI Sky when there are branches etc that have sky showing through. It works just fine for sky over distant mountains etc.
I find the Control Line one of the most useful masks as it does such a good job in most cases.