I'd either run a Modest nature if you use Salac Berry, or a more defensive EV spread with Leftovers to match the slow nature of Calm Mind and potentially beat out random Surfs and such. Consider Dragon Pulse over Shadow Ball, which also receives excellent type coverage in tandem with Aura Sphere, hits a bunch of Pokemon neutrally for more damage, and does more to Garchomp and Salamence.
Could the defensive evs of the Bulky Dancer set work with a few more in SP. Atk then Sp. Def?