How do you choose the size and boundaries of document chunks?

I look at the content and users' questions. A chunk should contain enough context to be understood. I don't want to cut an exception off from its rule, or a header from its table. But a chunk that's too large can bury the right information in unnecessary text.

I can compare several splits on the same questions and check whether the needed chunk is found. Partial overlap between neighbouring chunks helps at the boundaries, but it duplicates data and increases cost. I keep the link to the document, page and version. Sometimes I search a short chunk but attach the larger section it belongs to for the answer.