Nice, just got all 24 medals. ?-8 took two tries but I made the mistake of putting my strongest/fastest in the worst starting position the first time and they cleared the stage with one boss left remaining. Honestly only advice I can give is keep the far left starting camp empty, unless you have a really strong team, because one of the other teams will teleport on that path later to take the boss after a barrage of cannons weakens it making it easier. Fast squads are not really needed for this one it seems and I found an average of 500 speed on all squads, including the helper, keeps the group close together for the most part.

Good luck