The S4S fontstack is brilliant for making Google fonts available in your project. As you have found though because the stack CSS runs on the page which the stack is dropped on, then yes, you need one per page.
There are ways to change the font selection and style on all the pages in the project using Kiki Pro by pulling down the Google font you wish to use in the global header code then using the global CSS container to style the title using that font.
That gives you more of a ‘set it and forget it’ experience.
If you would like to learn more about how to do that I’d be happy to work through it with you. Just raise a ticket over at:-
and I’ll show you how.
Enjoy Kiki Pro!