> Using another layer of window capture doesn't work very well as I'm sure you know - it gets super laggy!

Oh, don't I know. I last looked into this when I had to produce a video explaining the FLP theorem. In the end I opted to just TikZ everything and avoid the iPad route because I couldn't get anything working acceptably well.

(Though I never tried just adding it as an video source directy, I assumed there had to be secret sauce in QuickTime.)

Thank you so much for the info!