Interesting approach.
I for myself use the MC for optimizing cruising, and I work with
required L/D for safety - exclusively.
The good thing about required L/D is that there are no assumptions
whatsoever to it, it's plain geometry.
In Alpine soaring (which I've been doing for the last couple of
thousand hours), with my 47:1 ship I feel safe with a required L/D
somewhere between 20 and 25, and unsafe above 30.
That still depends on meterological conditions (end of day vs high
winds...). I once had 20:1 in a 40:1 ship and I didn't make it :-(