We have a post on security monitoring console design guide that talks about the general principles and application to larger setups. As for yours, since there will only be 16 cameras, it can be simpler. Perhaps two monitors at most - one dedicated to displaying either cameras or a security client GUI and the other that the operator can switch between different applications as they need.
John, can you please expand more on the security client GUI?
I think other than the CCTV system, we must find an easy way to provide information from the intruder alarm system, providing the guard with an extra alarm keypad is not a good solution. We can do this by integrating to Crestron and provide a very nice custom GUI but I think I prefer something non custom directly from the alarm manufacturer or something that integrates easily with not much programming and designed just for this application.
By 'security client GUI', in this case, unless you have access control, it would likely just be a multiplex display of cameras.