Also you can add a hotkey for switch between screens, for example if "ctrl + alt + arrows" change the workspaces makes sense to make "ctrl + alt + shift + arrows" to change between screens
It should have been includes as default for the version 3.0, hum....
Then you can switch to the other screen, and then move between workspaces, move back to your main screen and switch them, organizing workspaces, windows, screens, and everything fast and easy 
