I'm trying to think of what the book said, but I'm sure it's best to do it after the first time S.reading/dipping. Unless you weren't able to activate too much. Then I'd go with once you were able to recall a good portion of what the book was about.
I don't think it would even hurt to make a mind map after each time of activation. You could just add to your current mind map each time until you were satisfied with what you had learned in the book.
personally, if I mindmap I like to do it as I go, just to help remember certain points of the book.
-jesse
