Chromasia Photoshop Tutorials

Looks like The Nightingale's (of Chromasia fame) new Photoshop tutorial is up. It's titled "LAB Color mode: part two" and can be found here. Since it's part two, you might also be interested in part one.

I haven't actually checked any of these out, but the sample, on Tonal Range and the Curves Tool looks very detailed and well done. I'll have to read in more detail later. Thoughts? Are they worth the money?