In the words of Stephen King -

Write with the door closed. Edit with it open.

You have fallen in love with your writing. More than that, you have become enamored with the process, not the product. The where and how is up to you, cowboy; do what you want to do. But stop fetishizing over it.

Do you know what an asymptote is? It's that thing you never reach. It sounds like you've already made two attempts at finding it, and are now digging in for a third round. How do you know when it's done?

- See, I know it's done when I realize I'm adding shit for me, not for anyone else reading it. And I stopped doing that a long f'ing time ago. So I know it's done when I've edited it once.

The rest of this shit is process, and it's tedious process at that. "cafes or study rooms?" You write where you are. I wrote 60 pages of a screenplay on the flight from Narita to San Francisco once. My choices aren't your choices and your choices need to be personal, reasonable and repeatable. You're asking the equivalent of "how do you take your coffee? For I wish to drink coffee the way other writers do so that I may be a writer."

You wanna know how to really knock this one out of the park?

WRITE SOMETHING ELSE.

Now go back and edit this. Got anything to add? No? It was done already. Yes? Well, you wouldn't have gotten there if you kept remixing it.

Just write. All else is artifice.