Apparently, according to the GAMME documentation, migrations can be stopped and then restarted again and it will continue from where it was stopped.

Has anybody done this? Is it a simple as clicking cancel, and then at a later date simply choosing to start it again. Assuming that I want to split the csv file with the users I wish to import (i.e. I'm thinking of running more instances, each in their own VM, to speed up the process) will it be clever enough to not duplicate previously imported emails?