These times assume a building speed of 1 second per block and are rounded to the nearest minute.
50 mass = 8 minutes
100 mass = 17 minutes
500 mass = 1 hour, 23 minutes
1,000 mass = 2 hours, 47 minutes
2,500 mass = 6 hours, 57 minutes
5,000 mass = 13 hours, 53 minutes
10,000 mass = 1 day...