I was working with one of my customers on reports they needed to deploy in Japan. The customer asked me how to convert the rulers in design and preview to use metric units. I had never done this before, but I knew there was a setting that mentioned this in the Page Setup window (File>Page Setup) so we went there first. That changed the page sizes to metric units but didn’t have any effect on the the design or preview rulers. Next we went to the “View” menu and tried changing the Product Locale to Germany, since that country uses metric units. This changed the ruler to metric, but it also put the entire menu and all the GUI labels into German. Right below this menu option is a similar menu item called “Preferred Viewing Locale”. It wasn’t really clear how this was different but we tried that next. That changed the rulers to metric without changing the language of the product.
On my own installation of CR I only have one option in Product Locale (English), but I have dozens of options in the “Preferred Viewing Locale”. It appears that these are installed automatically, while the full Product Locales are only installed if you select them at the time of install. My customer had the full list in both places.