Scheduling emails on your gmail account to be sent later at a specified time is no more a headache as this Google sheets script by Amit Agarwal of Digital inspiration makes the job as simple as possible. Unlike other third-party apps like Boomerang or Right Inbox this script doesn’t ask you for both read and write permissions for your entire Google account. All it needs is you to authorize your Google account and grant the necessary permissions. Make a copy of this Google spreadsheet with the scheduler script on your Google Drive to get started.
Amit Agarwal also provides a simple and straight forward video walk-through to make your job even more easier as it can be watched above.