I've had the opportunity to play a shaman recently (level 49), and noticed
that mana/health regens at 6 second ("tick") intervals. At first I
thought Cannibalism to be inefficient, but after discovering this I found
timing the stand -> cast -> sit pattern between ticks, I could use both
effectively (med and cann).

I believe clarity (Cassindra's Chorus) puts a "clarity counter" on
everyone in the group. When the tick occurs, the counter is removed and
additional mana is granted to the holder. This would explain why it is
possible to weave one other song in addition to clarity without diluting
it's effectiveness.

I was thinking about this topic because I don't like the common ideology
of "direct mana addition per pulse," when starting/stopping the song
doesn't add anything over simply singing it straight (despite the doubled
number of pulses). The big question, of course, is: Will the Cantata of
Replenishment stack with the Chorus of Clarity?

Athren