Of course, the last ten percent of the design work was the part that took the longest out of everything. It was the refining, the precision fitting, and the attunement process that made a Custom Mecha into a work of art.
There was no way to cut corners on it, even if everyone was worried about the next attack and when it might happen. The Galen had been resoundingly defeated, but it was the first battle, and traditionally those were used to sound out an enemy's strength, not as a deciding factor for an entire conflict.
Even if they thought that the humans were working with the Darklings, they would almost certainly be back. It might be an ambush or a hit-and-run sneak attack intended to deal as much damage as possible before their ships were boarded and cleaned out by the Darklings, but Max couldn't see a scenario where the Galen simply didn't attack again.