Relevant note for this multi-hit Ready move discussion:
while Ready Effect job points affect every hit of these attacks, Unleash Effect job points act like WS Damage+ and only impact the first hit.
It's simple enough to test in Abyssea-Misareaux, building up Azure light until you get an infinite supply of JA reset chests for constant Run Wild/Unleash. Atrociraptors at Conflux 7 only have ~6k HP @ level 95, and you'll have Favorable Correlation bonus against them so Pet:Attack is way over cap. It's a guaranteed kill with a single hit of Sweeping Gouge.
3000 TP Sweeping Gouge was doing an average of 10745 damage, which almost exactly matches the average against level -1 Wild Rabbits.
Unleash Sweeping Gouge
Minimum: 14697
Maximum: 15403
Average: 15050
The average Unleash Gouge is ~1.4x the non-Unleash average, so the numbers are as expected. The only tricky part here is that the chance of the first hit missing is 1%, so it took a while before I saw enough samples to be satisfied.
Some examples of Sweeping Gouge hits with Unleash (where the primary hit deals the killing blow).
And here's one instance where Unleash was active but the first hit missed and the second hit connected (so no Damage+ bonus from Job Points).
With that in mind, I think the theoretical maximum for Sweeping Gouge is just shy of 60k with Unleash and AM3 (or ~70k when you have Unleash and a source of Triple Attack like Atma/cites).
This is the highest one I've gotten so far (with extremely poor pDIF rolls):