Per User Spamassassin

To enable per user settings do I only need to add the file /home/[user]/.spamassassin/user_prefs and make sure it is owned by [user]:[user]?

To enable per vmail user, can I add the file /var/vmail/[domain.tld]/[vuser]/.spamassassin/user_prefs and ensure it is owned by [user]:mail?

Is there any other required configuration to tell spamassassin to look for these files?

Thanks.