I now know It's possible to do ALL of Phase 1 time with only 18 people...

[Nusa]

We started wtih air, then water, then fire already spawned, then undead...back to back. And we took only 45 minutes doing it. Another bunch did earth, but clearly we had enough time to do that too. We were pretty pumped after that run, I gotta tell you. (But a little sad for the bunch that were originally supposed to do fire and undead but wiped instead.)