Copy Region Options when creating master pages.

I've done this and it works perfectly for allowing editors to add new pages based on an existing template:

"The Copy Region Options setting lets you choose a page to copy region information from. I would normally use the page that I copied to create my Master Page. This ensures that when an editor creates a new page, all of the templates and any other options on those Regions are already defined. They just start to edit content."

But what I'm confused about is whether I need to keep that original-page as a live web-page on the site in order for the new pages to be referenced from it?

The original page will be a dummy and not be holding live content.

And if I want to make changes to be reflected across all the pages do I make them from the master page in /templates/pages or in the dummy web-page that I'm referencing, or both?