No idea on either count.

I was in the gifted program and offered multiple grade skips at 8 after taking a test (I have no idea which), which was the earliest age for the GT offering locally. My parents didn't need to advocate because the elementary school psychologist had determined I needed substantial acceleration and offered an initial double grade skip. (I was a "showy" child, like my DS.) So ?G for me, based on that limited info.

DS2.25 is like I was as a child, but on a steeper trajectory. When I benchmark his milestones against the Ruf estimates and the children of other parents here, he looks at least HG.

What is to give light must endure burning.