I'm no pro minstrel or anything but each Ballad gives you a stacking buff (2 of them actually) up to 3. So what I do is alternate Minor Ballad -> Piercing Cry -> Minor Ballad (Piercing Cry/any other cry or call if Piercing Cry is not reset) etc..etc.. Once I have 3 ballad buffs up and Coda is activated you can then do Coda -> Cry of the Chorus -> all other big hitting skills. Coda puts up a damage buff that you want to use and you immediately want those ballad buffs back up when Coda consumes them.
So it sounds like you try to take advantage of both buffs by alternating?
I'm surprised by how hard a time I've had tried to answer this question! I've googled the heck out of it but all I'm finding is people contradicting each other with different advice. Maybe it just doesn't matter all that much in the end.