I recommend that you just start sending all 30k mails and send us an email to firstname.lastname@example.org. I will then clear the limit for your project every 30 minutes (or so), and SoSci should automatically resume sending further mails then. By the end of the (work) day, all emails should be out.
I will also check the database for how many email addresses are invalid. If I understood you correctly, you used a single-opt-in,no double-opt-in, meaning that some addresses will be invalid. If that exceeds let's say 500 addresses, it may be necessary to postpone further mails to the next day in order not to trigger spam shutdowns.