7 of the 8 teams choose a deck from their vault for each of their matches. Light splits their vault into two pieces, one for each player, and then each player chooses a deck from their mini-vault for each match.
I think we're pretty well off. We get an extra round of scouting to see what the winner's vault looks like, and we probably won't have to face Gravity. I have a feeling Zeru is going to use a RoL/Hope to slay Fire. Darkness will use GotP/N to beat Earth, of course. Right now we should probably look through the recent decks of Light and Darkness to try to piece together their vaults.