May I ask, why use video for this? Or, to make question more general, why is everyone so obsessed with these jerky, stuttery, smeary internet videos that show barely recognizable geeks with gadgets in badly lit settings?

To add insult to the injury, Flash videos do not even show well on Nokia tablets and having 3-4 of them inlined brings MicroB to its knees.

So, can I suggest that you use normal screenshots and text instead? This will let readers freely browse through lessons (not possible with videos). The readers will also be able to recognize taught UI elements (barely possible with internet videos) and won't need to wait for the video to download over a shaky connection. Finally, with text you can organize your lessons hierarchically use hyperlinks, and have a table of contents. All this is not possible with internet videos.