Use migration files with the same number of rows, and run the batches at similar times during the day. Then compare the total ...

Use migration files with the same number of rows, and run the batches at similar times during the day. Then compare the total running time for each test batch. This helps you estimate how long it could take to migrate all your mailboxes, how large each migration batch should be, and how many simultaneous connections to the source email system you should use to balance migration speed and Internet bandwidth.