ultram, one thing I'd do is to first try to find out what the kindergarten curriculum and classroom experience is really like at this school (if you haven't already). Many of the things you worry about in your OP were never an issue in our kindergarten - reading was broken up into small groups based on ability, math included basic skills that your ds already knows, but it was primarily made up of applied problems so that even though the skills were easy for my kids the actual problems were new. There was a lot of group work, and there were subjects taught that were interesting, and ways for kids who thought deeper to explore deeper. It wasn't ideal and it definitely didn't offer a pace of learning at the pace our EG kiddo was capable of, but it wasn't mind-numbingly boring either.
The one question I have is you mentioned the sibs of many of the kids in the gifted magnet school within your school don't go to K-1 grade at the same school - is that because their neighborhood schools are different or is it because their parents are purposely not sending them there? If it's the latter reason, I'd want to know more about why... that may be a sign that advocating isn't going to get you much of anything. OTOH, you said your school places students in K with teachers after a few weeks of observing where they are at academically... so that sounds promising that the school is aware of the need to differentiate.
Good luck!
polarbear
