What is the best way to get more impact on your language Wikipedia? Who were your best instructors? Your best students? Your best Ambassadors? What can you do to recruit more people like your best instructors, Ambassadors, and students? How can you carefully discourage anyone who didn't contribute quality content from participating again? How can you bring people to your program who will improve Wikipedia the most?
Do you need to create additional roles? Is everything you had in the pilot plan necessary for your second term? How can you adjust the plan to get the most out of your volunteer time without overwhelming your participants?
Be creative. It may be that doubling the number of instructors will simply double the impact. Or maybe you can determine a way to get students to contribute more content. There's no one right answer, but your experiences in your pilot should be enough to guide you in the direction you think is best for expansion.