The application calls for qualifying score on IQ test and/OR out of level achievement test. I would have take the SAT or ACT and then decide. That's just my 2 cents.
The info on the application and website says that you need
both IQ and achievement at the 99.9th, not just one or the other. If you have one but not the other b/c the child has only done out of level testing, but not IQ, for instance, they do have the portfolio option. My understanding w/ the portfolio was that it was for children who hadn't taken one of the required tests, not for kids who had taken the tests but whose scores were just a bit too low.
I don't know for sure how much they would be willing to consider kids who are just a bit too low as we've never applied, though. One of my girls is in a similar spot w/ the WISC VCI at age 7.5 at the 99.7th with scores of 19, 17, and 15 and with a second administration of the WISC having the VCI at the 99th (scores of 18, 18, and 12). I don't have any good reason to believe that this kiddo would be a candidate for DYS, though although her first WISC PRI was in the 99th which does put her GAI at the 99.9th. It seems to be the highest score she's had on anything, though, so we are viewing it as more of an outlier than an absolute indication that she is that able.
In your case, if you strongly feel that she is DYS material, though, it might be worth starting with the SAT and seeing where you go from there. My eldest is also not a fast child and has anxiety about timed tests. She has gotten through the SAT with no major issues and scored fairly well nonetheless.
