My wife took it at Northwestern several years ago and it was about an 8 or 9 hour affair due to the number of students... I was in small rooms for both of my takes and was in and out in just under 5 hours.
@david.busis last option seems like the easiest to me, especially from the professor's perspective.
Also, I just began the course and wanted to let you know that I've really enjoyed it. Tremendously helpful and well worth the cost!
I'm honestly starting to lean towards not retaking. It'd be great to get into Penn or Duke, but I might do ED at Northwestern and get that 150k scholarship.
... that give you a different perspective on the world that can ... not to say that the perspective of those students is less ... would bring a genuinely different perspective to a classroom discussion/interaction ...