I had the same mindset as you - I did the Knewton course for about 3 weeks (2 weeks while working FT, and 1 week without work prior to my scheduled test).
While I believe it is possible to finish the course materials (all lectures, assessments + hw problems, and 5 CATs), I do believe that it was too tight a timeline to fully absorb everything to your maximum benefit. For me, getting through material in 3 weeks as not that bad, but I felt that I didn't have the time to go over my errors, which makes for a big part of truly improving your score.
Knewton was a decent testprep course, but to utilize it exclusively in your 2 weeks may not be the best idea. Ideally, you would obtain an understanding of your weak areas, and then focus on resources that may more specifically help you address your weakness. (MGMAT SC
for SC, GC Tests for Q, etc.) I personally blazed through the second part of the course just so that I could qualify for the "50 point guarantee", at perhaps the sacrifice of really targeting and improving my weak points.
Anyhow, that's just my experience - I wish you the best of luck!