What is the best age for correction of internal eight characters? How to correct children's splayed feet?

Empathy! I have been an insider since I was a child. At that time, my parents didn't pay attention to it, and I didn't know how to correct it. I still feel inferior. Since I found out that my son has an inner eight, I immediately became alert. I looked up a lot of information about how to correct children's splayed feet, and I also used the foot pads bought online, but my son always said that he was uncomfortable. Later, I fell in love with insoles made in Codman, Germany, which may be related to the customization of insoles made in Codman. Now it has been used for more than a year, and the internal splayed foot has been improved a little. And what is the best age for children's eight-character correction? 2- 14 years old, because children's bones grow rapidly during this period, and it is easier to correct them. Hurry up!