audio question for ex

shooting a small performance at a school, this is a very small stage in a classroom. i iwll be on a riser about 30ft away, they have no audio at all, just projecting. i want to hang a mic down in the middle of where they perform to get a somewhat better signal than the cam mike on my ex. the stage area is roughly 25-30 ft across. was thinking of hanging my sennheiser 835 mic down in the middle about 3ft down from lighting scaffolding, and will use my lectro wirless plug. will this get me much off them or should i use another mic instead?suggestions