I got an email the other day from an aspiring screenwriter who had an idea for an unusual structure for her screenplay. She asked whether I thought it would be safer to stick to the traditional three-act structure and "maybe just drop in a few more unusual elements."
Of course it's hard to give advice on a specific project when you don't know the story or the details of the alternative structure, but in general I agree with this advice from painter Courtney Jordan about mixed media artwork:
"Mixed media artists can't be faint of heart. You have to be brave to try mixed media techniques that you've never tried before, but I've discovered that you won't get anywhere--and you kind of feel let down--if you don't push it enough to show you are actually mixing media."
I think the same is true for screenwriters and novelists. If you have an unconventional way to tell your story--and you're using it because it's the best way, not just to be different for the sake of it--go for it.
Trying to stick to the rules and be just a little unconventional probably will make your novel or script just as muddy and unconvincing as a mixed media artwork by an artist who lacked the confidence to go all the way.
In the world of screenwriting, scripts that stand out often are not the first ones to be bought, but they capture the attention of those who read them. Those readers know they're dealing with a writer who has the courage to venture out of the safe territory. Ironically, they may then hire you to write something more conventional, but at least you'll have your foot in the door.
(For tips on writing, from inspiration through to publication, get a copy of my book, Your Writing Coach, published by Nicholas Brealey and available from Amazon or your other favorite bookseller.)