I'm incredibly confused at calling courier not a suitable font for reading. Screenplays are meant to be read and understood quickly and the monospace font allows for that more easily than any other font. In fact. Courier has been the staple of editors in publishing houses anywhere from short stories to epic novels. Times New Roman is getting to the levels of "acceptable" but that's mostly all that is allowed or else you're unprofessional and don't understand the industry.