Excellent suggestion on IAS. I've not been able to find a copy (the elementary school didn't seem to have one, and the local library doesn't either), but I did find this .pdf: http://iu19giftednetwork.wikispaces.com/file/view/IOWA.pdf/163401557/IOWA.pdf

If the .pdf is accurate, then I get a total of 65 points, which puts him in the "excellent candidate for acceleration" category. So I'm feeling pretty good about deciding to go for it.