[xwiki-users] Multiple Wikis Best Practices

I am on XWiki 5.2. I would like to create multiple wikis so I'm trying to figure out the best way to structure them and manage them. I am going to leave Home as basic wiki that will be a starting point for all users and it will allow them to navigate to the other wikis. I want to create a wiki per department at work. I would be the main person managing them all. I want to customize the wiki template but I don't see anywhere to do that. I want to make sure that all new wikis will have the same branding, some core macros, and extensions.. I am also confused about how to manage extensions across the different wikis? Do I need to go into each one and install the same extensions or is there a central place to do that? We've been using the wiki in a single department so far but now that we are going to create multiple wikis I'd like to move the existing content to a new wiki (so that Home is very pure and used only for navigating to other wikis). I figured I could export the current content and import to the new wiki but when I did this the applications were not installed so there's missing macros and APIs.