@Charles_Weaver did an interview with Mark, who works closely with Clear Creek and has a Youtube channel. The conversation is fascinating.

Much is probably not new, at least to longtime users and people who followed the rhythm series, but I'll take this to say this: any time I have a question about the Mocquereau/Gajard method, I'm always learning something new from the pre-conciliar authors (Mocquereau, Gajard, their interpreters slash disciples…) or from going back to Laus in ecclesia, usually about something that I just happen to see in the next set of propers. Or I listen to Gajard (by the way, the remastered recordings are really beautiful). I don't know if it's possible to "memorize" every last nuance, some of which are contradictory. Or I realize that, perhaps, there's inconsistency; why bother with the scandicus if you're just going to make them like the salicus? That's an unanswerable question as far as Mocquereau's reasoning goes, and I stick to the markings, but it's worth noting. In any case, going back and reading, and rereading, and listening (sometimes with a pencil to highlight the neumes brought out — and as Dr. Weaver likes to point out, the roots of those details are in the introduction to the Liber Usualis)

I think that goes for any system or way of approaching not just chant but any kind of music; Le Figaro recently interviewed William Christie of Les Arts florissants (incidentally, he's got some wonderful insights on France and America as an expatriate who has French nationality as well — sadly it's behind a paywall stronger than Ft. Knox), whose style has evolved somewhat, I think, over his long and illustrious career.

By the way, since I'll eventually get Dr. Weaver to respond — the schola, distinct from the choir, of Ligugé is doing some interesting stuff on their CDs.

Hopefully part 2 goes up soon!