[CentOS] logwatch customization question

Logwatch is installed, and I am assuming by how empty /etc/logwatch is that it is running from defaults, which I find in /usr/share/logwatch/default.conf/services

I want to customize ONE service. dovecot.

Do I copy /usr/share/logwatch/default.conf/services/dovecot.conf

to

/etc/logwatch/conf/services

and edit it there,

or do I have to copy ALL default.conf/services/* there and modify /etc/logwatch/conf/logwatch.conf to look there?

The README is rather not helpful on this.

How do I modify ONE service (and not just make the changes in default.conf that I have seen in a couple howtos.

thanks