Mark, good luck with the Spitty - I recall that a Gunson's Carbalancer was never to far from reach

Simple. For me, so far, then thing about luminosity masks is they huge range of tonal areas that can be selected for not just exposure editing, but any adjustment or enhancement. The sliders in LR are broad range and only cover darks and lights, so they are a bit crude - albeit usually more than good enough for most pictures.
I downloaded the pdf, haven't read it yet, but my word if it is as dull as the linked video presentation I think I'll have to chew my leg off.