It seems like I should be able to re-target to a list, but I can’t seem to be able to manage a list once I’ve added anyone to it. I’m wondering of this is the best angle of attack to send a follow up email to those that never opened it.
For a specific newsletter you need the reports extension which has the retargeting feature, otherwise you can use the general maintenance option to set in a list who do not interact with the plugin since a period of time.