Luckily your dd is far enough ahead grade-wise from your ds that the sibling jealousy might not be as much of an issue. Plus, maybe the different sex thing might help it too (Dottie has a daughter in the same grade as son and they seem to be more at ease than my two sons who are 2 grades apart & only sharing math class).

Definitely ask for the testing--worst case, they say no, right?