Depends how much offence you want coming from your second line and how much can be replaced by Perfetti’s improvement. Right now there’s a clear top 2 in 5v5 scoring with Scheifele and Connor around 45 points. The next level includes Vilardi, Ehlers and Perfetti at 33, 30 and 25 points respectively. Then you have Nino, Lowry, Appleton and Namestnikov all around 20 points.
If your goal is 75 5v5 points from the second line, I think it’s reasonable to count on 30-35 from Perfetti next year. Then you only need ~40 from the other two players, which you could probably get from players like Namestnikov and Iafallo.