Play time before Duo unlocked

How long does it take before the Duo is unlocked. The promos mention something about "second half" alongside 20-30 hours of game. In our case, local co-op games get far more actual play than anything else.

I remember the Tier 3 Duo hull being unlocked by the time you finish the second galaxy. Don't take my word for it though.
EDIT: yes, please, do take my word. I poked the devs and they confirmed.

You can start playing Duo type hulls on the third mission of the second galaxy. If you want to skip to the second galaxy, you can do so through the main menu by selecting Single Player > Skip Intro Galaxy.