Yes, I understand that part, but it doesn't disprove that such an experiment could show isotropy. Instead, it says that it would always indicate isotropy, which is not entirely useful either, of course. I'll dig deeper into the publication behind that section when I have the time. Nonetheless, my original point still stands. With a highly synchronised clock, you could measure the (an)isotropy of the one-way speed of light. To determine whether the time dilation issue is surmountable I'll have to look at the actual research behind it.