TheDman wrote:
There is no right or wrong time to use the masks. Luminosity masks are just more ways of making selections, which you can do at any time in your processing workflow.
Tony Kuyper's actions are the gold standard, not only for luminosity making but also for web sharpening and a host of other things. Plus they come with Sean Bagshaw's extensive video tutorials that show you the best ways of using the masks, which will quickly turn you into a competent user. Can't recommend them enough.