Gaffer's Query: One-Page Pitch Placement in Your Dev Workflow?

Hey everyone, Tomáš here, gaffer by trade, always trying to learn more about the whole production pipeline. I've been digging into project development lately, specifically the idea of the one-page pitch as a crucial tool.

My current project is a short documentary I'm trying to get off the ground, a really character-driven piece about a local craftsman. I've got a decent outline, some key visuals, and a rough budget, but I'm wrestling with when to really nail down that one-pager. Is it something you tackle almost immediately after the core idea sparks, even before you've got much else? Or do you flesh out a good chunk of the story, characters, and maybe even some visual references, then distil it all down into that powerful single page?

For those of you who've successfully pitched and produced, how does creating and refining your one-page pitch fit into your actual development workflow?