Open source maintainers: How do you work with tech writers?

I am considering mentoring tech writers to contribute docs to open source projects, but I want to make sure I don't create additional work for open source maintainers. Can you help me understand:

• If a tech writer wants to contribute docs your open source project, what would you want them to focus on?
• How much effort would it take on your part to help them make effective contributions?
• What would make you nervous about their contributions?