I just got back from Captiva last week where I was teaching blues harmonica at a Gindick Jam Camp.  One thing I was reflecting on was how much harmonica (or any instrument for that matter) is like shakuhachi and how the music shares a lot of similarities.  We spent quite a bit of time working on teaching players how to use dynamics in their playing by exaggerating the differences in volume between certain notes and phrases.  This is not unlike how I understand meri notes to be played.  On one of my lessons with Kurahashi Yoshio we had a great talk about making meri notes very soft to add feeling and depth to the music.  Another thing we spent a lot of time on at the harmonica jam camp was allowing space between phrases.  It is the same thing with Honkyoku.  Ma is very important and I notice that many beginners rush from phrase to phrase with no regard for the ma (space) in the piece.  I still find myself doing this from time to time when my mind isn't with the music completely.  I try to play the phrase and then pause slightly before the in-breath.