This will be the only way to obtain those rare wings, either buy with lots of zeny at the auction, or try to trade one with a player who's already purchased a pair.
15atk seems best as there is a card called Echio coming out in the newest updates that will overpower the wings since Swordie class gets an extra +500 hp outta wearing it. It also is an armor card, feel free to look yourself on RMS :]
15 atk with no drawback though seems cool, the only other possible option that is truly better has a -3def penalty *Porcellio Card which is also armor*
Pretty maybe, but an effect equal to slapping a hatter card on to a mink coat is a bit on the low side for something that is expected to be auctioned off for millions and millions ._.;
Now it'll be far more respectable (and one step closer to the fairies to build themselves an inexistent homeland)