Having experimented with other luminosity masks toolsets, such as Raya-Pro (http://www.shutterevolve.com), I believe I have now found the ‘ultimate’ luminosity masking set up, which is: TKAction and Lumenzia - together!
Lumenzia creates masks in a different way to TKActions, not through channels but through taylored use of curves. Lumenzia is available from: https://gregbenzphotography.com/lumenzia/
At $70 for the pair, these two Photoshop add-ons represent real post-processing value.
As to how and when I use them? Simply every time I use Photoshop.
Thus, after a few Lightroom corrections my workflow is a round trip to Photoshop and, using both TKActions and Lumenzia, which work seamlessly together, I exploit the tailored adjustments that the self-feathering luminosity mask-based approach allows.
As a simply example of the control that an LM-based workflow brings, the following single image, Sony A6000 capture was given the LM touch., which allowed me to target the trees and bring drama into the sky. Note that the sky was there in the original capture, it 'just' needed developing in post.
Bottom line: if nothing else watch the video tutorials on TKActions and Lumenzia. But I’m sure you will decide that $70 is a real bargain.