TripleB - I'm in a rush and really don't have time to give much worthwhile advice, but there is one piece of your concern that I'd think through - the 3rd grade standardized testing - you need to find out if it's actually meaningful in the long run. I don't know anything about where you live, but where we live it really doesn't mean *anything* for any given individual student - so if you were living here, I would take that worry out of the equation all together. What it's used for in my area is to assess school performance, and although parents receive a copy of the results and it stays on the child's school record through elementary school, it's really non-consequential.
I would definitely take into account how your ds feels about school right now - our ds was extremely bored in early-elementary and it's something that he internalized rather than sharing with us at the time... and that came back out in a not-so-great blow-up later on in school. Sorry no time to explain at the moment! Just something to think through.
Best wishes,
polarbear
