Best way to modify event reminder email format

Hi to all,
my colleagues ask me to change the text and format of the reminder email in order to adapt them to some formats already used with other procedures that we are migrating Indico. Now, what is the best way to do it? customization? Please could you tell me how to do it? Thank you. Simone.

You can use template customization (the template is event_reminder.txt) but it may be somewhat messy since the blocks in that template are rather big.