When will her next rerun be

I'm saving for her, currently I think 17k primos (whatever 105 pulls is worth) might get Zi Bai, but it'll be good if I lose. I really, really want her, I love her gameplay, her design, her lore and backstory, and also I just want to play archons with my sister (she has Furina). BUT I WANT HER. I'm already prefarming because of my lack of patience and my immense excitement, AND I NEED TO KNOW WHEN SHE WILL RERUN. Also, random question, is Fischl or Kujou Sara better for her? (Both are c0 Ik c6 sara is better)