Migrate cPanel Domains to another cPanel server

My existing server ran out of VAR space and was nearly out of disk space so I have purchased a new server and need to migrate the domains from one to the other. There are about 150 domains totaling about 400GB of data. Both servers are located at Softlayer in Dallas. The server OS details are as follows: Old - Redhat Enterprise 4 running cPanel WHM 11.32.6 New - Redhat Enterprise 6.4 running cPanel WHM 11.36.1 Would like to do the migration this weekend May 4-5, Saturday night off hours, i.e. between 1 or 2am and 5-6am CST. The nameserver is on the existing server so the nameserver support will need to be migrated with the server. Most of the domains are standard running Menalto Gallery, Wordpress, Joomla, etc. We do have one non-traditional product called Strongbox which provides password protection. [login to view URL] In addition to the migration we will want the new server hardened. The last person who hardened the server left the server susceptible to reverse DNS problems.