That the measurements from the slow clock transport synchronisation method are equivalent to the Einstein synchronisation and its isotropic speed of light can be interpreted to show that the one-way speed of light is indeed isotropic for a given set-up and not anisotropic. The problem with this is that anisotropy could not even be measured if it were to exist in this context. But this is definitely not a clear-cut zero sum game, there’s no evidence suggesting anisotropy while there are observations that would at least suggest isotropy, but neither possibility can be ruled out. However, my initial point was that, could you have ultra-synchronised clocks, you could potentially be able to draw a reliable conclusion. But I’ll dig into the publication the Wiki entry cites for the time dilation part in the slow clock section when I have the time.
That the measurements from the slow clock transport synchronisation method are equivalent to the Einstein synchronisation and its isotropic speed of light can be interpreted to show that the one-way speed of light is indeed isotropic for a given set-up and not anisotropic. The problem with this is that anisotropy could not even be measured if it were to exist in this context. But this is definitely not a clear-cut zero sum game, there’s no evidence suggesting anisotropy while there are observations that would at least suggest isotropy, but neither possibility can be ruled out. However, my initial point was that, could you have ultra-synchronised clocks, you could potentially be able to draw a reliable conclusion. But I’ll dig into the publication the Wiki entry cites for the time dilation part in the slow clock section when I have the time.