Sorry for being offtopic but regarding Xahlee’s article: you don’t need to see all windows at once. Key is having virtual desktops as many as you like, easily reachable via a hotkey like super+1 (I use 10 per display). Then you build you desktops by purpose. For example, I have always a terminal and emacs on 1, a browser on 2 (full-screen), signal at 8, other on 9 and mail on 10; Some other stuff on my second display. So when I start using an application no already there, I reach out for the virtual desktop 3 on display 1 and depending if need to have some reference for working on that, I put documents on display 2. It’s pretty simple. Switching desktops is super+N, between displays I use super+<>. I hope you get the idea.
END OF BEING OFFTOPIC