Well, at the example of 20 quanta as the lowest,
if the divisor is 3, it will be 20|21
if the divisor is 4, it will be a 5|6
if the divisor is 5, it will be a 4|5
6 and beyond is not well functional.
But since 20 might take a while, and the values will surely be fluctuating, i'd go with the divisor as 3 or 4