re: 3e children & youth questions

[Curmudgeon]

Yes, 3e is officially dead but I'm still hopeful for some answers with canonical authority and no, I don't expect to be making a habit of these sorts of 3e questions.
21 was the age of majority for much longer than 18 was. For those times when 21 was the age of majority, should the Youth advantage top out at -12 points and reduce at 2 points/year or should it still top out at -6 points and reduce at 1 point/year.
I've always presumed that if the age of majority were 15, say for an Ice Age campaign, characters can't take the Youth disadvantage because it hinges on there being a discrepancy between being physically adult development and being recognized socially as an adult. Is this correct?
Finally, how would the point difference between an adult and child scale up in a 500 point supers game?
Would it be:
1. 250 points (children have half the points of an adult).
2. 150 points (children are 2 point levels [3e B11 sidebar] lower than adults).
3. 450 points (children are a flat 50 points lower than adults).
4. something else (on some other basis).
As a final question, for adolescent characters (age 12-14) would a 75 point build be the more appropriate standard?