You might wanna try this set, I find it very useful.
Spiritomb @ Chesto Berry(Nature is your choice)
EVs: 252 HP/252 Def/6 Special attack
-Rest
-Will-O-Wisp(Cuts the foe's physical attacks, in case you didn't know)
-Dark Pulse
-Calm Mind
The set can do wonders, and is especially a good set for Spiritomb, because it has no weaknesses. And I give your set a 8/10.