I'm currently trying to set the default thread view to overlay for all of my users. I can set the thread view to overlay for myself through personal preferences, but I want this to be the default for all users.

Also, I'd like for the sidebar to be hidden by default with the user having to click "Show Sidebar" to enable.

Is there any way to accomplish either of these? I apologize if it's an obvious answer, but I looked around and couldn't find anything.