Need some suggestions on managing course variations

Hi all,

I've built a course for a client who now needs course variations for multiple industries. The course remains 90% identical, with perhaps differences in images or voiceover on a few screens. This is a burdensome situation as any general course changes now have to be made to multiple project files, multiplying the time required, thus additional cost to the client.

I would like to maintain a single master project file that would allow me to choose the course version I want before publishing, which would simplify changes. I first considered adding duplicates of the screens that vary between courses, renaming them to indicate which course version they pertain to, then deleting the non-applicable screens and renaming the applicable screens before publishing. But this seems like a very clunky approach, in addition to introducing the possibility of inadvertently saving over the master file with a modified-for-publishing-only version.

Has anyone faced the same issue and come up with an elegant solution?