Logging which account used which email address

I am trying to figure out what email address is being used by a specific IAM user. I followed the article here: https://aws.amazon.com/premiumsupport/knowledge-center/ses-iam-user-sent-email/ to log which IAM user is sending emails through SES. But I am unsure what dimension to use to also get the email address used. I can't find any documentation on the dimensions available for either Message Tag or Email Header.

Thanks, Josh