Grand Tournament vs Atlantis

I'm trying to get Atlantis's mask from the Grand Tournament and aim for Map 20, exchanging Emeralds for Gloves if needed to farm for star traits. However, due to a recent change in the Grand Tournament's rules (temporary? from the original 5 hearts to the latest 3), my strategy has changed, and I'm struggling to get a good rank,orz With 5 hearts, I averaged 2nd place, sometimes 1st. With 2 hearts, I'm getting 3rd-5th. With 3 hearts, even 5th place is looking shaky, TT;;; Random party composition is one thing, but the key really lies in spell usage (selection, timing, and order).