You can always try again in person when you arrive in Kyoto. I have done the Katsura tour 3-4 times, and being shepherded through really ruins the experience and is always a let down from what you read about in books. Shugaku-in is a nice experience, and Manshu-in, which is close by and does not require reservations, is a nice proxy for Katsura's architecture (which is not part of the tour anyways).