Never used Uwe's tool (we all miss him) but (don't want to insult your intelligence) are you aware of the many luminosity masking tools currently available?
I use Greg Benz's Lumenzia; Tony Kuyper has one, as does Jimmy McIntyre. There may be others. Most have free versions as well as paid ones. The free ones are simple to use, more limited but pretty useful. The paid ones can lead you down quite a rabbit hole with their complexity.
Good luck in your quest.
