I have written a Python script that iterates through rows of an Excel file and, for each row:

Gets an e-mail address, name, and name of attachment file to use
Composes an e-mail
Sends out the e-mail

I'm not sure if it's accurate to call this mass-emailing or if it is a candidate for being black-listed because it is sending out individualized e-mails. With a message submission rate of 5/minute, I want to throttle it (or have the limit increased to 100).
So my question is: Is the sort of scenario, assuming the limit is increased to 100, prone to black-listing?
It depends on how well you know the people you're mailing.
If you know them pretty well, it should be fine. If they're total strangers, the recipients might think it's spam and start blocking you.
I could help more if you told me how well you know the recipients.
Python Email via MS Exchange: Message Submission Rate Limit