This is probably the best moveset:
Calm Mind: Helps increase the power of Flamethrower while increasing Sp. Def, which protects against Water types.
Flamethrower: Powered up by Calm Mind. Good power, high accuracy, STAB, chance to burn.
Iron Head: Used to deal with Rock types, good power, high accuracy, good chance to cause flinching.
Stone Edge: High power, good chance for critical hit, type coverage.