I have (checks clock) sixteen days to finish a movie script.  This is actually fine.  A thing I learned from John Rogers is to write-over.  Each stage of the job - beat outline, treatment, screenplay – is built on the other.  Copy the rough beat outline into a new document and rewrite and add and expand until it’s a treatment.  Copy the treatment into Final Draft and rewrite and add and expand until it’s a screenplay.  That way, you only start with a blank piece of paper right at the very start of the process.  Every other stage comes with scaffolding and a base coat.  Works for prose and comics too.  Try it.  Just copy the previous document into the next one and start rewriting and adapting it.  Might not work for everything, but it might give you a leg up.