So what's up with screenplay structure anyway? Do you Save The Cat or have My Story Beat Up Your Story? Are you a three-act adept, a four-act aficionado, a fervent five-acter or do you scoff at acts altogether? Do you bravely embark on the Writer's Journey or do you try to have Something Startling Happen every minute? What teacher/guru/manual do you follow above all others? Who deserves to be deified, and who should be thrown on the trash heap of history? Or should you throw all structural models overboard and blindly follow your instincts?
Here is the secret truth. Don't tell anyone I let you in on it.
Use whatever works for you.
The only thing that matters, is that you are able to tell the story you want to tell, in the best possible way. And that means structuring the emotional response of your audience to maximum effect.
So they will feel what you want them to feel, at the moment you want them to feel it. So they will be ahead of or behind or at exactly the same place as your characters, when you want them to be. So they will be able to follow the characters' transformation, or thrill at their exploits, or rail against unjust fate when tragedy strikes them down - just as you planned.
In a way, the proliferation of different structural models is a blessing: it allows writers to experiment, find whatever method they are most comfortable with - or develop their own variations on a theme.
It also gives you the opportunity to select different structural approaches depending on the type of story you are trying to tell. Sure, most of the models out there are explictly Hollywood-based, but recently the Save The Cat website posted a convincing analysis of Michael Haneke's Amour, an art-house film through and through.
So, if a structural model helps you create, use it and don't feel guilty! And if they feel too constraining - ignore them! Just get that script written, and make it the best it can be!