Do this through Time Attack and also Survival on Normal.
Time Attack:
Level 1 = Color 3
Level 6 = Color 5
Level 11 = Color 7
Level 16 = Color 9
Survival:
Level 1 = Color 4
Level 6 = Color 6
Level 11 = Color 8
Level 16 = Color 10
Also, for Time Attack you don't need Golds, just meet the quota.