Example (I'm just throwing some numbers out there to illustrate):
1 person boxing 5 toons, with 1 stone every 5 minutes = 1 cyan for a main every 1h20m.
5 people with 5 mains, taking turns looting stones, 1 stone every 5 minutes = 1 cyan for a main every 6h20m
Time sink for boxer above to get Ultimate = 66h40m
Time sink for a non-boxer above to get Ultimate = 316h40m
I was under the impression it took 100 cyans for the ult charm, but your numbers = 50 total cyans?