First off, Cheerful Nature doesn't exist. I think you mean Careful.
Second, the best Skarm set is HP Flying/Spikes/Whirlwind/Rest. Whirlwind because Mr. Mime lols at Roar, and Hp Flying because it's the next best thing to Drill Peck that you can have while still using Whirlwind. But I suppose you won't be able to get HP Flying InGame, so Drill Peck and Roar works fine. I don't think I've ever seen a BP InGame anyhow.
Greek God.....Toxic doesn't work on Skarmory unless you have a TSS Team. Fly is alright in the game, because the opponent doesn't ever switch out. Don't advise it, though, because Aerial Ace/Drill Peck/HP Flying are all better moves. Steel Wing accomplishes no purpose, as Steel is a horrific Attacking Type. Skarmory needs no Defense boost, anyway, Base 140 is awesome.
~*CB*~
The 8th Champion