I like Carolyn K's article: Least-worst educational fit

We have been pretty lucky to find a good-fit school for our kiddo, but we live near a major metro area with several public self-contained GT options. Each of the schools have a bit of a different philosophy, so not all of the schools will fit all GT kids. And we have no clue what we'll do for our kiddo after his current program ends after 5th grade. But for now, we travel 45 miles to a pretty awesome school.

I can relate to the OP's post. Our kiddo also did not get quite enough after a grade skip, especially in math. Before we switched schools, we advocated quite a bit and did finally get the option for DS to pretest out of math units and learn new material with the GT coordinator when he tested out. Does your school have a math resource or GT coordinator? Maybe they could offer some help. Good luck!