1 candy 13 times:

1,00 00:05 N-Gacha
2,00 00:05 5*Candy
3,00 00:05 N-Gacha
4,00 00:05 5*Candy
5,00 00:05 N-Wild 1
6,00 00:05 N-Wild 1
7,00 00:05 5*Candy
8,00 00:05 N-Wild 1
9,00 00:05 N-Gacha
10,00 00:05 N-Gacha
11,00 00:05 5*Candy
12,00 00:05 5*Candy
13,00 00:05 N-Wild 1

No girls so far and uselless drops

3* R-Gachs or 3*Pudding

1,00 01:30:00 20 candy + 1* Wild3
2,00 01:30:00 20 candy + 1* Wild5 + Perom
3,00 01:30:00 20 candy + 1* Wild5 + Perom
4,00 01:30:00 1*Wild5+ Pudding
5,00 01:30:00 R girl
6,00 01:30:00 20 candy + 1* Wild5 + Perom
7,00 01:30:00 SR gilr
8,00 01:30:00 1*Wild5+ Pudding
9,00 01:30:00 1*pudding half
10,00 01:30:00 1* R Gacha
11,00 01:30:00 20 Candy R Gasha
12,00 01:30:00 1* Wild5 + Perom
13,00 01:30:00 20 Candy R Gasha
14,00 02:30:00 30 Candy, 2* Glasses, 2*Radar
15,00 02:00:00 30 Candy, 2* Glasses, 2*Radar
16,00 01:30:00 R girl
17,00 01:30:00 1* Wild5 + Perom
18,00 01:30:00 1* pudding + 1*pudding half

SR-Girl once out for 18 tries. R-Girl 2 time out of 18 tries.

From daily missions players can earn 1 R-Gacha per day. Free players need luck to get the monthly SR-Girl.
So far donating one R-Gacha a a time been best thing to donate...