Change default file location in Outlook

I have 2 users who currently use their inbox as major storage for their emails in Outlook (1 is at 75MB, the other at 25 MB). I am working with them to encourage them to save their emails to another location but they want to have “the least amounts of clicks to save it”. I can’t see a way to change the default location for Save As from the email message (default currently is My Documents) without changing the Registry. Is there a way to change the default file location to a file location of their choice?