I would think that the success would be for a 1 or even 2 day class. First of all the store would make more money by spending one designated time frame to teach many students and I think that as students go even though it'd be great if we all could have that mentor when we needed them we all can't afford those indiviualized lessons. I've been lucky twice with my favorite teacher where the other student didn't show up for class and I had her attention and learned so much more since it was just us two but I couldn't have afforded a one on one. Also I think that when you have many students each brings their own prior knowlege to the class and that can help others learn little tricks that you may not have thought of or heard of before. I've always learned from some of my fellow classmates.