There isn’t any “norm” that can be given to you for these timeframes. Your network and xfr rates will vary due to many variables. Xfr time does depend on size of mailbox, so all you can do is perform a test. Try moving four mailboxes, maybe resources or test mailboxes and document how long that takes. You can move 4 per move command (the 4 will move consecutively within one move command window), but you can open several move windows at a time on the 2003 Exchange server. Try moving 3 or 4 move windows concurrently if you have that option.