Set Point

Trying to work with my son at home, he's 11 and have a couple questions

1. What is the proper set point for older kids and younger kids?
What I tend to see is most players have a set point above the eye to form this L, but younger players have a hard time getting the ball to the rim so their set point seems to be under the chin closer to the chest. Should I make the younger players have the set point above the eye.

2. When do you get to the set point?
I see some players get to the set point as they bend their knees and then release as the uncoil, but others bend their knees and then get to the set point on the way up.

Coaches love to hear that parents are practicing with their children at home, its great!