Our son plays for 3d and I still don't understand the pecking order or how the various Express teams are put together. As far as this tournament is concerned, I am not a huge fan of it, despite that we came away with the "national championship." IMO the Crab's tournaments still bring together the best collection of youth teams, but even that one had a few teams which probably shouldn't have been there.
I would prefer to see it as event that does not allow anyone who has participated in a high school program to play. | 
