Raken. The To'raken are the ones being used predominantly in the WT attack. Galgan lets Suroth have the bulk of the Raken, but she's not allowed to touch the Raken.

From the BWB they can fly 3-4 times the speed of a horse with a range of around 300 miles. Raken with Turan and there'd be some raken with the WT attack and potentially at way points along the way for that. It shouldn't take too many days to hear of it.

Of course it also depends on timelines as well and my track record of predictions isn't that flash hot, but what I propose is at least logically consistent with the forces in the field and character actions. That doesn't mean it will happen, but it's not a 'Mat will channel and bond Tuon' level theory either