Did not even think about the clones for Double Spark, since her damage is rather weak until she gets Nightmare Spark (use terrian bonuses), I even got her MAP attacks from clones, at 120 power it's pretty funny.
Simply drag the time and occupy a comfortable position, you have nowhere to rush in this fight.
On the last two spell cards, I just blow her with all that I had, even break her dialogue with Yukari during the Beauty of Nature (she still restores 30% HP until she talks four times with Yukari)
In any case, it was Hard.
Lunatic, of course, must go with full upgrades.
I actually used only one bomb, on that spell card that forbade the pass through fields, since it prevented me from approaching Yuuka.
And do not forget about Kanako, her skill giving Acceleration + Assail really turns any fight into your favor.
I did so that Youmu could make two attacks using Soul, and Tenshi could have made two attacks under Bravery (I did not have time to make the second)
and took the up Knockout for Yuugi - it was a mistake.
Utsuho because of the bug could not raise her power above 170, becoming the target of the Nightmare Spark, she could not counterattack (she not have enough 100 ~ 200HP)
Well, as a bonus, Youmu avoided 7 of the 8 Valor Double Sparks (MAP), she just hit her to grit.
PS:
Oh, it was actually Ultimate Spark, I somehow thought it was a Abyss or Nightmare Spark o/
It was really ... scary.
Edit:
I think to try the Challenger Hard against Makura in the first pass ... this should be funny?
In any case, this is the final fight ... they are always pretty easy, but this time, you really have a chance to lose on the final spell card.
However, I still put Yuuka in first place in terms of complexity, Makura will take the second, Yumeko third.