Spike Cannon, if it works with Skill Link, would be a guaranteed five hits, at 20 BP a pop, for 100BP with 100% accuracy. After Shell Smash, and with max Attack EVs, it'd pack a punch. Although perhaps Return would be just as suitable.
Thing with the Smogon link you posted is the only move they list that I don't have is Rock Blast. I was already planning on Shell Smash, Icicle Spear and either Razor Shell or Hydro Pump. Since I missed Rock Blast, maybe I should just include both Razor Shell and Hydro Pump, for breaking physical walls and special walls, respectively.
Maybe Toxic would be nice? Or Explosion to go out with a bang?