Jon,
I’m really impressed in your tutorial skills. Very clear and concise instructions spoken in a very clear and concise way.
The WebVfx description is fine. The only thing I would have pointed out is that although the “data-control=‘10:30’” instruction is to run the animation at 30fps for 10 seconds, this is only for the benefit of running in the browser. In Shotcut this instruction is ignored as the filter will run for the total duration of the clip and will have the frame-rate that is specified in Shotcut.