There is no substitute for "hand's on" experience, unfortunately. I don't know of any book that will make you a guru on anything, especially in the timeframe you are looking at.
IMHO, that timeline is foolish and unwise (feel free to quote me to your management ). Rushing into such a major change (and it really is a major change moving from 1 email system to another) only opens you and the company up to further issues and long nights spent debugging "what's broke".
Then you'll be tweaking the SPAM system to work as yoru old one (it'll take quite some time, as I'm learning).
I'd recommend an installation and testing period before cutting the domain over to the new system.
While I don't remember the specific packages, the RHEL install will probably be missing some requirements that you'll need to install using "up2date" (I don't recall if we needed to install anything manually). There were a few packages we needed to install before the ZCS installer would continue.
You'll also want to download and install DCC, RAZOR and some/many of the SARE rules for Spamassassin. It'll help (although we're still training the system as a large amount of SPAM still makes it through, but it may be out settings).
Good luck, but don't rush through it.