Hmm, a Latias lead seems like a good idea.
So, Latias doesn't get Taunted, and sets everything up. I switch in either T-Tar or Gyara, and DD as they switch. I then have 4 turns of Light Screen, 5 turns of Reflect, and 3 turns of Safeguard. That's enough to wreck havoc.
I'm changing items on...