It's up to you. Shed Shell lets you escape from trappers like Magnezone but the leftovers could really help Mory.
Forgot to explain the EVs spread ahah
Basically 248 HP / 188 SpD are necessary in order to take on Latwins, MegaGardevoir, MegaDiancie ecc. 8EVs in Speed let you outspeed Azumarill...