My foray into the smoke genre, if nothing else, is improving my PP skills.
The selection process is proving more complex than what I've done in the past when I've limited
myself primarily to using the Color Range command. I've found that by adding a Threshold
Adjustment layer provides a numerical basis for the amount of white/dark that I want to select
when I utilize that Color Range command. Always followed by Refine Edge command.
Case in point: In this image I made seven various selections and subjected each to a different
Hue Saturation Layer. If nothing else, it is interesting.