eh, if you want 6* girls, there's a rainbow medal gacha as well.... each attempt is 150 rainbow medals and 11 premium draws
but it's 3k gold per attempt so... yeah... you can get up to 750 rainbow medals total just from the offer, and they made it a 7% drop rate for 5* with a 3% drop rate for 6* girls...
depends on how much you want to spend, but i got one draw of it and traded instantly for Herbaceous Peony. That now gives me 5 Slice girls... (Herb Peony, Acacia, Fritillaria, Dusty Miller, and Wax Vine)