Hey thanks all!

I initially thought that the themes that came-with the program were internally tucked-into the code somewhere, so I bought another theme with which to experiment. As soon as I downloaded it I discovered that Coffee Cup was parking stylesheets both in the program folder and the documents folder, and it was easy to do what Inger suggested and create a permanent edit.

Worth noting as well that any images that get tweaked should also be parked back into their originating folder for the theme, as any that are modified within a local drive website directory will get overwritten every time the calendar is re-exported to that folder.