Teams should be determined through a method of ongoing evaluation during the season. Rarely, if ever done. Tryouts are an ancient practice that should go the way of the dodo bird (except for the kids that are unknown - give them a fair trial by putting together a group of them in an open trial, or if there's only a couple just invite them to your regular practice). But takes a lot of resources! Over the years have had many kids email and say "can I join your team?" I say, yes, you can come tryout for 2 sessions. I tell them if I know at the 1st session they aren't good enough I will tell them, and if I know they are clearly good enough at the 1st session I would tell them that too. The benefit to this assessment method is that kids see very quickly if they are good enough or not by competing directly against the kids they are trying to join.