I think this is different, with Khan Academy there's no pressure of ending the course. Here you have a few months and there's an incentive to go and complete the course. I'm not expecting 100% of the people to complete the course, but I do expect better completion rates than Khan Academy or Coursera.
I love divvy, but a file input field is still easier. Both options require you to go through a file browser to find your file, but a file input doesn't make you resize any windows then resize them back.