AI3 grinding is generally supposed to be a "mindless" activity -- something you can do while you multi-task.
The Fire Bolts need some thought and reference to the Fire Bolt damage table to use correctly, so it's not the best card for the purpose of AI3 farming.
A Shrieker Rush deck (Mark of Time, 17 Stone Pillars, 6 Graboids, 6 Shriekers, 1 Short Sword or Dagger) has a simple enough strategy: play out your hand (play Graboids before Shriekers), evolve all Graboids, attack until victory. Repeat ad nauseum. Games played with this deck are fast, systematic, and repetitive.