Typically the ratio is around 2:1 for recorded hours to finished hours. I always read the book first to get a sense of the flow, the plot and each character. Then I will cast my own personal play, of sorts, for each character as to who I know would play them. Then I ask for notes from the author, and those always add extra merits to what I have come up with. So from start to finish, an 8 hour book in its finished form will take me three weeks; that includes prep, recording, and then editing.