Smart sister you have there. This site is full of very knowledgable people and most will respond very quickly and share their experiences. Your never alone on BYC that's what I love about it.It says 20-22 for the vaccination itself. However, I think I'll probably use the TB as it's small and manageable.
I love BYC. Otherwise I'd be all by my lonesome in this! NOBODY I know has chickens. Except now my sister, who is a newbie of 2 weeks. And was smart enough to get big fat chicks that the hatchery vaccinated for her.