CASPer as a whole is such a scam and it infuriates me that it is being used by an increasing number of Canadian med schools when there is so little evidence to justify its use.
Three weeks is more than enough time. The goal of the interview is to get to know you. You shouldn't have to practice and rehearse that much if you're being truthful and honest in your answers.
I grew up in NS before moving away in high school. Still have a ton of family there and have a genuine love for and desire to return to the province to stay.