I used HTML emails for a couple of my documents if you want to check those out:
https://coda.io/t/Clocking-In-a-Timesheet-Gmail_tf229A0YZ1g
https://coda.io/t/Email-Newsletter-Planning-Sending-Logging_tk1vRHOrQHt
The timesheet has a table with a formula map equation that you could compare against.