From what I saw, flow is attached along the full length of the skirt with minor exceptions:
Once in a while, the last, lowest tufts get a little crazy, but flow never reverses.
Compare to a non-skirted, non-wheel-disc Miata:
Artist-enhanced! Because he didn't put on as many tufts. But
view the video, and I don't think you'll disagree with the artwork: There's zero attached flow on the bodywork behind the wheel arch/tire.
Last test: tomorrow may be nice enough to do some coastdown comparisons.