That wasn't one of our challenges, but I'm wondering if it's 'too late' to have him switch into 1st grade? Will they allow you to observe for a few hours before he enters?
Ovserving the new school's kindy and 1st grade will give you a definite idea of where your child fits in. (And allow you to observe the teaching style - is there a sense of humor and adventure?)
If I recall correctly the little section in the back of Ruf's book matching the accomidation to LOG and School type, then if he's Ruf Level 3, he is likely to severely need a gradeskip, unless the new school is a very affluent area. I can't remember exactly what the word was about Ruf Level 2s but my guess is that a skip would be good, but perhaps not essential, again depending on the level of the school system.
If you make a formal request for IQ and Achievement testing, will the new school do it? Can you bring a small sample of his work in his own handwriting for the new school to look at? (Some math, a baby book report, the sight words he can read copied by him, a little story about one of his science or history interests - or explaining what infinity is in his own words
Good Luck
Grinity