I don’t believe in adjusting line spacing or using alternative Courier 12 fonts in order to reduce page count — the script will still read long, and may seem denser than it is.

But I do sometimes extend the right margin of an element by one or two letters in order to eliminate an orphan. (The old Cole Haag manual from the IBM Selectric days allowed some flexibility with right margins.)

My main weakness is redundant or unnecessary dialogue, and as your Chayefsky quote points out, trimming dialogue makes the greatest improvement on a read. It may even force the writer to rely more on subtext than on exposition.