If you are going to use whitelists/blacklists, you are always going to cause false positives. Rather use Meta Rules as per
Improving Anti-spam system - Zimbra :: Wiki.
Also, implement greylisting as per
Improving Anti-spam system - Zimbra :: Wiki and you should find a vast improvement.
While it would be nice to have a graphical interface for domain administrators, I haven't found this option anywhere yet, so the CLi is your best bet.