What I've been doing lately is using

/use 13
/use 14
/cast Elemental Mastery
/castrandom [target=targettarget, harm] [] Lightning Bolt, Lightning Bolt,
/cast Lesser Healing Wave

on one of my guys, he pops lesser healing wave 33% of the time - to increase the # of LB's, just add an additional LB into the /castrandom - to increase the # of heals, add additional commas to the /castrandom line.

I think eventually I'll set it up I have 2 shammies casting LHW's 25% of the time, as right now healing is a little short (I do have a way for all to heal the tank of course, but I'd like to reduce it's requirement for heroics and reduce healing aggro).