If I'm recalling correctly, the CAT testing above 1st grade assumes some literacy on the part of the student-- I'd watch out for that, since you're trying to get a read on levels above 1st grade.
I mean, you could certainly read questions to him if you were proctoring it yourself-- and there are homeschooling supply places (Family Learning Organization in Spokane, for example) that will mail stuff to you and score when you return things priority mail-- but that wouldn't be exactly like standard testing conditions.
I'd probably do it that way, myself, just to get a feel for where he ACTUALLY is, since the literacy is likely to produce an artificially low ceiling otherwise on anything 2nd grade or up.
After all, you plan to reevaluate in a few months again, right? This would be a way of being VERY low-key about testing, too-- just do a section or two each afternoon for a few days, and don't worry about a big trip to the testing center or anything.
All of the tests have their own flavor in terms of test item design and wording/style. The CAT worked for us because it seems to relate best culturally (we live on the same coast).
