The morning's writing dilemma

Somewhere along the line, I need to figure out where the exposition about the parallel world fits into the screenplay I am writing.

I can't think like a novelist.  I can't even think like a short story writer, even though some of the same rules of economy apply.  I have to think like a screenwriter.

I love novels because they can provide so much detail about characters and places.  You really get to know them as their reader.  When watching a film, you are barely introduced before you get swept up into the storm of activity.  It's the story, the plot and the action which captivate you (possibly aided by a pretty face or two and even majestic, beautiful or intricate scenery, because eye candy never hurts).  You might care about what happens to the characters, but you don't really know them.

With those thoughts in mind, how do I go about turning thirty-five pages of essentially conversational exposition into a scene or two of informative backstory so that I don't lose my viewers in lengthy conversations?

Do I write scenes that I know I am not going to use?  Will it help me write other scenes, especially those I have to create from scratch?  Will it be helpful just to get them down on paper (or up on the screen) and therefore out of my head?  Or is it a frivolous use of valuable writing time?

It would be practice if nothing else, and practice is almost never a frivolous use of valuable writing time.

With the novel writing exercise of last November, the keys to the kingdom were most certainly found in quantity over quality.  In comparison to fifty thousand words, one hundred pages formatted to favor white space on the page seems like a molehill, and quality and quantity might just be able to switch places on the priority list ... or at least sit a bit closer together.

One hundred pages I can do.  It's having a distinct beginning, middle and end happening to interesting characters in an interesting setting crammed into those hundred pages which is the real challenge.