As you said, there are three requirements what your boss need.
1. Moodle support.
2. Narration support.
3. Significantly reduce the file size for web sharing.
I have a way out and it has worked.
Make a non public Video using snagit or some screen activity capturing tool with a Mic.
Upload it on youtube with non sharing option turned on. This imples till the time you do not share the link Video cannot be viewed by any unauthorised person.
Moodle Support = YES tested for 2.7+
Narration Support - Yes ...as it is a Video
No burden of File Size at all.
We did it for 100 GB HD video. Only difference here . It was a really training video instead of ppt.