Keeping courses lean

I'm building a huge course and using the following strategies to keep it lean. I would like to hear anyone's thoughts about these strategies and garner a few more if you have any!  Thanks everyone!

Current Strategies:

1. Place common assets (like nav buttons) with their states and triggers on the Master Slide

2. Use web-object to call out to larger files like videos and place the videos somewhere like JW Player. (Bonus: whenever I need to update my course I just upload fresh content to JW Player in place of the old file and the course is instantly updated, without cracking it open to refresh and re-publish).

3. For screens with many objects, consider taking a screenshot and saving it as a png file, then bring that one object back into the course as a picture.

Wondering About:

1. For commonly used audio files (like a bell or sentence that is said over and over again) I wonder about giving it one place to live and then setting a trigger for it at the beginning of the timeline for every screen it needs to be on.

2. Would it be beneficial to set the background to a picture at the Master Slide level.  I've tried so that I can lay nav buttons over it at the Master Slide level but haven't quite figured this out yet.