I finally configured amavisd-new with my Postfix configuration. It is a simple setup using only ClamAV and Spamassassin. However I do want to implement DKIM through amavisd-new of course that requires a newer version of amavisd-new than is in the packaging system of the release of Ubuntu I am running. Further I would like to switch my Linode to Debian over Ubuntu. It is safe to expect some downtime soon likely tonight as a result of upgrading through two releases. I will post a part 2 once the upgrade is complete and I implement DKIM with the details of what I did.