Don't too bother with Bad Pulls or Banner, All girls you get can Raise her Stars (even from 1star you can raise to 7stars or above).
As for banner Girls Guarantee Get 100 point For that Girl (Guarantee Increasing her stars to 6)
if you get Banner Girls, do not happy too much, Banners END and your girls stuck from that stars(lol)
as me my self, always hope to seing 'Duplicate' character for increasing stars from Pulling.
Just Leave it to "OMAKASE" and you will be fine ~