I'm developing an application containing several view controllers.
A few of those view controllers should use the
View controller-based status bar appearance
The Default style is the default! So you do indeed add code only where you want the Light style.
Here's the thing to keep in mind. The API is that every top-level view controller dictates how it wants the status bar to appear. You probably don't have many of those. So not much code will be needed at all.