It took me three times through the CD's as well as multiple times through the practice exams - mostly memorization of the tricky questions. Your memorization mileage may vary....
Taking the practical test within the next few weeks. The commercial flight training has been by far the most fun and the most educational. Forced night flying has been the best training - gaining good judgement by experience

Utilizing the rudder was a good thing. Xcountry by pilotage revealed that I depend on the GPS too much. Good VOR practice as well as continued instructor input throughout the commercial training was invaluable... find a really good instructor. They're worth every penny of extra training hours. Refined Xwind landing technique was also invaluable. More instrument approach practice was also done during the training - proficiency is priceless.
The commercial rating will not be of much direct benefit in the RV(experimental restriction.) However, the training has be worth every minute.
Dave