Subsail has a handy list of all magazine copies that subscribers have purchased but have yet to be marked as sent.

app.subsail.com/manage/fulfilment/

This list will show in detail which copies need to be sent out. You can also mark copies as sent (with dates) from this page.

There are also two filters you can use to view more detailed lists. You can browse by issue and by order source.

Customer accountsSync subscriber data to Mailchimp