This should probably go in the Haku match-up thread... but I'm too lazy to go it right now and I figure it if this is important enough to go in there, Hex will move it (Sorry for making you do extra work Hex).
I can't hitconfirm off of a single D sword. So I always do 2 D presses in Dia mode so that if the first D sword hit, the second one will auto combo and then I can confirm the rest of the combo. Against Hakumen, if he Yukikaze's the first D sword, the second one will whiff and then I just lost a bunch of damage. Rather than risk that, it is just better to go with Luna where that doesn't happen. Luna also does more damage which is a good thing. There are some other reasons but I don't have enough time right now.
What would a guide consist? A video? A fleshed out wiki? Or a really good post in a thread?