• Prefer structure tags over headings if you're writing a file specifically for import — they give you subsections, which headings alone cannot.
• Don't mix intent: a stray single # line meant only as a large heading, in a file that has no structure tags, could accidentally be read as a section boundary if you add a second one later. If you're using tags, that risk goes away entirely.
• Keep files under 2MB. Large docs import faster if split into a few smaller files first.