Yeah, Ryan was very supportive and the Glee producers were very flexible with Darren’s schedule during the first few episodes of season 3, Darren was going back and forth between LA and NYC to film GML.

http://darrencrissnews.com/post/22156165436/darrens-great-and-im-very-supportive-of-his

Shari Springer Berman: The part of Lee, played by Darren Criss, that was hard [to cast] because it was scripted that he is a Backstreet Boy impersonator. It had to be someone who could get up and dance. And he has to be a romantic interest, but it is scripted that he is much younger than her so there has to be a connection but it also has to feel a little weird for them to be together. It was hard to find the right person. Bob thought we should look at the people on "Glee," and he went online and found this interview Darren did with Rolling Stone, where he sang all the answers to the questions. He was like, "Shari, come here and look at this! There's something special with this guy."