How to address a Sergeant/Drill Sergeant via text?

I'm really thrown through a loop with my RSP deal. One of the NCO's, who used to be a drill sergeant, texts us all every month before drill. I never really know how to word my responses or questions. In person or on the phone I do the usual "Good morning/afternoon/evening, Drill Sergeant", but that seems awkward over text. Should I just skip the greeting and ask the question?