Schedule event in Flowable to send emails to multiple users

Hello ,
How do I set up a schedule event in Flowable to trigger at the end of each day, sending emails simultaneously to multiple users? The workflow requires dynamically creating email content for each user.
Our approach involves storing data for email content creation in a database. Timer event, which is configured as a start event, will activate a Service task which has Java logic to retrieve email data from DB, and generates unique email content for each user. Subsequently, another Service task will handle the email dispatch to individual users.
To pass email content from the first Service task to the Email service task, can we utilize process variables? How can we iterate over the list of users within the Service task to send emails to each user individually? Also any configurations needed so that performance is not impacted ?