For me, the worst problem with this test is the media: it's changing constantly, so the test we could have made with 24x media could be useless nowadays... And the tests we can make now will be outdated in little time. (I think I could make some generalization about quality of brands for the future but it would be only a guess).
I don't have much time now to test all that media.
I was wondering why you wanted to use audio cd's for your test instead of data?
Apart from the extra correction layer in data CDs that cfitz mentioned, the only way I had to count C2 errors at that time, was Feurio (an only audio program).
Anyway, everybody can test his media easily with the tools available today.
Those WSES/CDDoctor tools must be great to test CDs, but I don't have a LiteOn drive. I guess those programs don't stop when finding critical errors: in that case, they are perfect...
Let's see if CDSpeed can support my LG to count C1/C2 errors...