One can only hope. Considering how Ace/Une seems to dislike clothes, I'm betting she'd wear the smallest one she could get away with though. XD on that note ever read fashion_mistake's drabble about the Whitebeard Pirates' reaction to female!Ace's clothes(or lack of) (http://fashi0n-mistake.livejournal.com/42644.html#cutid2)

Luffy would have had one of his zen moments

He would, wouldn't he? Just when Ace's finally has a good speech prepared...or Luffy'd just declare it as a "Mystery" and be done with it...