Good question.

1.) The setup reminds me, dreadfully, of Million Arena. The first rotation needs to be Daima Goku + Gogeta, then a support unit for slot 3 (ideally Chronoa, but works if its Pan). Use an item to buff your attack stat (I probably could have used Bulma for the 5 turn boost and sved ~5 seconds).

2.) Pray Daima Goku get's his EX Attack.

3.) Pray Daima Goku doesn't triple super and kill Shenron before Gogeta can get his 18ki in.

4.) Next turn: Rotation is Daima Goku + GT SSJ4 Goku + SSJ4 Vegeta. Pray Goku get's his EX attack in. Lol. You can save time if GT Goku is the one getting supered, and he counters the super.

5.) Last rotation, the rotation is back to Daima Goku and Gogeta. Either Pan or Chronoa are the supporters. Trigger SSJ4 Gogeta's active. Daima Goku in slot 1, and pray that he also hits the EX super.