Only macro I use for BLM is a mouseover macro for Aetherial Manipulation so I can zip around the field without having to break my targeting.
/micon "Aetherial Manipulation"
/ac "Aetherial Manipulation" <mo>
/ac "Aetherial Manipulation" <f>
/ac "Aetherial Manipulation" <t>
So if I'm mousing over someone, I go to them. If not I go to a focus target I've set up ahead of time. If not I go to my current target. Otherwise I get an error and question my life choices.