Abuse Darkness cause it causes good damage to them. Kill Mindy first cause she has the lowest HP, and her defeat means that the Sisters can’t use Delta Attack. Heal, Attack, Heal, Attack, it’s that easy, really.
However, this was last I played it, so it may be inaccurate, since I can barely remember ever fighting the Maga Sisters. I don’t think its even spelled right. I will be playing Final Fantasy X-2 again this Christmas, so I will know by then.
If you focus on her (she only has like 5000HP iirc) it is easy enough and can be done at mid to late 20s.
same.