I did
today and we know 261 of gravities cards before they have to discard, they are only allowed 245 as of next round so they are discarding pretty much everything.
Also since the winning decks from round 2 are still intact in the vault since they discard from the losing decks, you can add some of the round 2 decks to what ou have compiled for round 3 . Example: gravity won with discord blackhole with 6 BH in Round 2 in Round 3 they only used 2 BH, that means that 4 more are lurking somewhere in the vault.