I cannot disagree more strongly with Birkal on this subject. This step of the process is the only step where we could completely neuter CAP5's ability to deal with Dragons; if we give it the wrong typing, it will be guaranteed to be unable to switch in, and it will be extremely difficult to find a way to actually kill those Dragons. Specifically, I would say that Dragon itself is a terrible typing to consider, totally destroying the whole point. Grass is at least viable, since not every Dragon carries a Fire attack, especially our prime targets, the Lati@s twins. Sun teams can run many different ways of dealing with Waters (Venusaur, Dragons of their own), but SubCM or CM Refresh Latias are practically impossible for a Sun team to actually kill. Heatran just won't cut it. Luckily, most of the non-Lati@s Dragon Pokemon are slow(er) and can be handled as much with movepool as which typing, but in terms of beat the Lati@s twins and taking most moves used by Dragons neutrally, there is nothing that does it as well as Dark does. The other combination that does well, accounting for a few more possibilities such as Superpower on Dragonite or Haxorus or Focus Blast on Hydreigon, would be Dark/Ghost. Barring a Steel type, we are not going to resist Dragon, so neutrality to all moves carried by Dragons is an asset, and no other type destroys the Latis as effetively as Dark does.