Thanks both of you. There is so many options, it's hard to make a choice. I want to make everything at the same time but it would take a 10 girl team for that.
A crit/weak themed team is a good option but it's hard to give her all the weakness bonus. I'll need two weakness girls or 3 memory slots filled with weakness FM on the other girls to redirect all the ability bonus on Sparaxis.
Speaking of weakness, the new weakness FM with +40% for self would be great on her if they do one version of each (just need to adapt the weakness to the current enemy).

And still speaking of weakness, I foud something useless with the new buff table. Actually, you could give a weakness of her type to a girl if you have less than 3 girls with different types. With one Harbanthus and 4 magic girls, you will have two magic girls with added magic weakness. I'm pretty sure it change nothing at all but it's interesting to know how the abilities actually works.