Not a lot of experience so I will let others chime in.
We just did this for K and one thing that comes to mind:
- The GAI score there is the "real" IQ score in my opinion, but they may want to use FSIQ because they are not as familiar with the GAI. So you try to prepare a little one line blurb yourself about what that index is and why it is typical to substitute it for the FSIQ. In your case both are definitely high enough for any gifted cut off I've ever seen, so maybe it won't be an issue?
Definitely read up on advocacy a little first so you aren't caught off guard.
In our school they seemed to go through the process of taking the scores and filling out the paperwork for the sake of doing the paperwork. If you know what paths other similar kids have taken and what types of things the school has offered before it may help you prepare. Do you have any kind of gifted org in your area you can use to connect with other families? In our case we did find one and it really, really helped. Also talking directly to the district gifted office in addition to our local school helped us learn more about what was available.
GL