Remember how f'd up the tourneys used to be with U13, U11, A,B,C, always whining about teams playing down a bracket, it was always a mess. Grade based is clean, and the top teams at the top tournaments don't argue about this holdback nonsense. Unless you want to create a private school league, this is the best it is going to get. They aren't going to go age, as the clubs are not going to want to build teams all through MS, then have to re-build the teams in HS. You need grade based in HS, because coaches don't want to watch mixed up teams during the recruiting years.