Hello,
We dont really have a best practise guide per say as things change depending on which deployment options you use
The following documentation will run you through all of the product features and configuration options and will hopefully provide you the information you need
http://help.symanteccloud.com/symhelpContent/EN_US/MLWSSC/docs/WebSecurity_AdminGuide.pdf
Kind Regards
Richard Brittain
Tier2 Senior Technical Support Engineer,
Symantec Corporation