So, how long was each era?

[No_Nick_Needed]

I would imagine that after the Thirteenth, the Ascians would have spent some time analysing how and why they failed with their first attempt and coming up with the way that would eventually be successful. Also they were probably extra careful to avoid a repeat of their previous failure. Though they also didn't have to contend with the Source being devastated, so it could go either way with the first proper rejoining taking longer or shorter to set up, than the following ones.

I wonder, if the Ascians ever came up with any ideas of how to salvage the Void after all. To fully put Zodiark back together, they would have had to tackle that issue eventually... unless they believed that a 13/14th complete Zodiark was already complete and powerful enough to awaken and gobble up the final reflection himself.