I'm going to say this (don't flame) since skarm's best stat is defence, just give it enough (300 stat) and max hp and put enough in attack to make it decent enough and rest in sp defence which is the biggest flaw on it.
lol 300 isn't nearly enough; your Skarm will get beaten down by CBed attacks and the like before long. Skarm shouldn't be staying in against special attackers anyway since most 2hko it, so Special Defense is useless.
second I'm going to say: don't use both in one team, both have lower sp defence which, from a fire pokemon, two of your team goes down.
Fire Pokemon are nonexistant in the metagame. Bellyzard, Blaziken, and Houndoom are used as novelty/fun sometimes, but that's it.
thirdly: you can't have both whirlwind and drill peck go with drill peck and roar. Sound proof pokemon of the likes of exploud eats metal arce when it comes to skarmory. and personally, I prefer rest over sub unless you have leftovers which even then, its risky with its low HP
Eh, personal preference. I'm paranoid about little possibilites, so I like Sub/HP Flying/Whirlwind myself. Ingame, though, it's nearly impossible to breed for good HP, so Drill Peck/Roar should be used there.