Quote
I will say though that GT kid #2 almost always presents differently than GT kid #1.

Amen to that!
DH wanted me to work with #2 because he didn't think she was getting as much exposure to letters and sounds as #1 had at the same age. This is because #1 had more 1:1 time with adults. #2's world revolves around playing with big sister. When #1 started K, I spent more 1:1 time with #2. She rapidly progressed from ABCs to picking up reading about a year earlier than #1 had picked it up.