zucchini sourdough

Summer has brought all kinds of fresh vegetables from our garden and we have a lot of zucchini. I've been baking tons of sourdough lately, and I'm working on sourdough formulas for my leftover zucchini. Anyway, does anyone know what % I should use proportioned to flour? It's a bit tricky because of the amount of water in zucchini, but I would take most of the moisture out. Thanks!