As for me, I'd prefer using "homophones" quite often as the aim is to introduce the idea of the same pronunciation with different meanings (we don't speak about spelling much - at least at this level), "homographs" are used to introduce the idea of similar spelling and different meaning. Actually, "homophones" & "homographs" are the two sides of the same medal - "homonym" that can be rendered as "having the same name" (as you know, the names are the same either in writing or pronunciation, though they definitely mean different objects)))