Hi,
I've done something similar for another project.
I already have a proof-of-concept implemented, that read all emails from the Inbox and Spam folder of a GMail account and sends them to another GMail account.
It's based on pure Java code, no Gmail API is used.
I can implement the rest of the requirements (reading from a spreadsheet and the scheduler) in less than a day.
Do you need a graphical interface for the program or a simple terminal program will do ?
Thank you,
Radu Tamas