But my comment wasn't (purely) a joke - since some drop companies only allow one person to book a particular name, and some names are booked months and months in advance, "whenever you like" is an appropriate answer when looking at the customer side of the transaction.
I believe the actual drop happens daily at 2pm Eastern Time, 11am Pacific. Hence the scramble. But perhaps you're trying to figure out on which day a domain will drop? I could pass you a link to a board with a lot of posts on this subjec, but I don't know if that's within the guidelines here...