For the rank beginner I think just playing a C box in G is daunting enough. The lack of an F sharp and crossed cords takes some getting used too, especally if they have had any formal music training.
It is safe to say that your web site downloads have shown you have the knack for presenting the information needed to get one started.
All that said, perhaps your second video for the more advanced players, could have a section on playing in alternate keys on the diatonic box.