Best Answer Rob , 12 June 2013 - 11:36 AM
If you've read about Base Theme, which is a very plain child theme, this will not add any styling or changes (as third-party child themes do). So, if you add the Base Theme to each multisite, your centralized styling and settings will be seen. However, the Base Theme lets you modify a functions.php and style.less or style.css on an individual basis. Base Theme is essentially invisible but it still gives you the option to modify things when you want, in each of the sites.
Use that one and you'll have everything you wish for.Go to the full post