Regarding bio banding, parents won’t go for it unless you can explain it.
Birthdays are simple. We understand them. I can look at the birth certificate and tell you their age group. So can anyone. Easy.
Biobands are not simple. You might have one definition for how to measure someone’s developmental age, but other people will want a different definition. Very few of us can figure out our kids adjusted age. Even if we can figure it out, it seems unstable. Do they age up every time they have a growth spurt? Maybe, maybe not.
This is why biobands are useful only for someone like USSoccer or Southhampton. If you need to evaluate 200 kids and the payoff is signing the next Mbappe, biobands can help, and they are worth the trouble. If you need to evaluate 2,000,000 kids and the payoff is slightly fairer rec games, you’re not going to bother.
And, despite what parents want to believe, ECNL and GA have more in common with rec soccer than with Mbappe.