What’s the best practice for prototyping both a desktop and mobile version of a website at the same time? Should they be in the same project file? Separate project files? I’m assuming the desktop and mobile version should not both be on the same “mockup page” (I’m not sure of the correct term); is that correct?
You can either organize your mockup pages as pictured (mockup heirarchy), or use separate projects.
The single advantage of having the separate projects is the ability to display the mobile and desktop screens simultaneously for the comparison reasons.
See the Mockup Hierarcy Feature for details.