Consider this use case: I have to give a speech, and I cannot give it extemporaneously (too long, too little time to prepare), so I have to use a manuscript. I would expect the typographical requirements for a speech manuscript are different than for, say, a newspaper article: It has to be very readable even from a slightly larger than usual distance (it may be on a lectern), it must be easy to find where are you where after saying a few words or sentenced without reading them, abut it should also not require more pages than necessary.
So what fonts, what spacing, what justification should I use? Are there proven standards for that? What do professionals (e.g. speech writers for politicians) do?