Ended up with a 1622 rating after 26 battles. Don't have too much time left so I think I'm going to stop here. My team was:
Magikarp@Mystic Water
Ability: Swift Swim
Nature: Modest (+SpA -Atk)
EVs: 252 SpA, 204 HP, 36 SpD, 12 Spe, 4 Def
-Hydro Pump
-Bounce
-Flail
-Splash
Debate the item for a...