[Blarg]

I don't think it will work well for the majority of people.

You tend to write differently for different lengths of material, because you have to. When you have to make major cuts, you're very likely to face a task not of editing, but of a lot of rewriting or even complete reconceptualization.

For instance, you can space out expository passages in a longer work, to make them less cumbersome and keep the work flowing. And you can have more of them. But say you have to start cutting a whole lot. Then you may find the story doesn't make much sense anymore. The story starts to fail. So what do you do? You can't really get rid of the exposition, but you can't keep it either.

Solution: You cram your exposition into some poor character's mouth who now has the task of getting away with speaking in a way that's dull and unnatural, maybe even comically so. (This is the part that often makes me roll my eyes watching movies. Bad Writing 101.) You've turned your character fairly baldly into a mechanism rather than a human, and you'll probably get caught at it.

The same thing goes for setting scenes, casually revealing dialogue slipped out here and there, little things that make the work flow and make sense and come together. Left with a lot of editing to do, you have to dump a lot of them, and may never find a way to get that wholeness of the work back, because it was written to be whole at a much different length, not the one you've got. The natural pace and flavor of a piece, and the motivation for characters, can vanish and leave you with a clunky frankenstein of a script stitched together from sexier sources.

Can you do it? Maybe, especially if you're Stephen King. But the man is world class at it, he has no length restrictions, and he has the experience of decades -- and he still screws up at it frequently. What chance do the rest of us have of consistently putting Humpty Dumpty together again?

It's just a naturally very hard way to go about things. It sets up a lot of problems up front, and it depends a lot more on luck and innate talent to get things right once you've got the ball rolling in random directions for indeterminable periods. If I have a story that's going to need to be done in 120 pages, writing one that will only properly pay off in 240 will likely make me choose different subject matter, different themes, more characters and viewpoints, different subplots and more of them, and radically different pacing. These are things that editing isn't the best tool in the box to fix, because the problem isn't the number of words. The number of words could be just right for a different kind of story. Writing within restrictions isn't just about the quantity of pages. When you write within restrictions, you change the nature of the work.

An example is to be found in your own short films. Was gravida coming out well a matter of editing out the car chases and the pursuit of a great white whale? Was the relatively stationary camera and quiet story with a limited number of sets and special effects in any way an accident? Writing within your restrictions made you choose the type of story, the setting, and the pacing. You knew where you were going, and that's how you got sensibly where you did. You clearly did a lot of thinking it out in advance.