I agree with Kriston that "flexibility and teamwork from both school and parent seem to be the best keys to whether public school will work or not for an HG+ child". In my case, our public charter school took pride in educating ALL students with GATE curriculum and challenging them in the same grade classroom. However, when I brought the IQ score to them, they said they believe they can challenge students with any IQ score in the same grade classroom without subject acceleration or grade skip. I have an EG kid. These kids usually need at least a subject acceleration if not a grade skip. They had declined our request for subject acceleration. I don't even want to try asking them for a grade skip. DS did not learn a thing this year.
As I thought much about ds' education, I realize our school (very small, only 100 kids in k-6) doesn't have the resources to accommodate him. So, I am going to take him out next year to homeschool him.
I have seen big schools in a big district usually have better programs and more resources to deal with GT kids. I really hope you have better luck than us.