Musharna or Polteagist for in-game Pokemon sword?

Question

Here’s the team I’m making:

Cinderace - pyro ball, electro ball, shadow ball, bounce

Toxtricity- shock wave, belch, boom burst, fire punch

Sandaconda- body press, earthquake, stone edge, zen headbut

Blastoise - surf, ice beam, outrage, skull bash

Leafeon - dig, iron tail, synthesis, leaf blade

And either polteagist- giga drain, psychic, dark pulse, phantom force

OR

Musharna- psychic, energy ball, shadow ball, dazzling gleam

Looking for a sp attack, sp defense Pokemon 

Polteagist has a high sp attack and sp defense but musharna has an even spread