Page Layouts

If I have 5 layouts in paper space and all are set up to an A4, how can I convert all at once to A0. Ive changed the first layout to A0 and back in the main menu clicked on 'set current'. Only the second layout changed to A0, all the rest are still set to A4. What now, do I really have to go in every layout and change each one individually?

If all the layouts have the same 'page setup' set current, then modifying that page setup will change it for all layouts. Otherwise, you'll have to go to each layout and set the desired page setup current. (If you had something like 50 or 75 layouts, then it could be automated using lisp, .NET, etc.)

Note that when publishing multiple layouts, you can choose any page setup at publish time, and it doesn't necessarily need to be set current.