[Feature request] strictly distribute plots evenly

[Ac3sRwild]

Could you add an option to always fill the specified number of disks evenly? Currently if there is a slower disk in the batch, and you are not creating enough plots to completely fill all disks, the faster disks will fill up first leaving a much larger amount of free space on the slow disk(s). I realize that if the number of plots created is not equally divisible by the number of disks then they will not be exactly even but the difference should only be 1 plot per disk which is still much better than the current scenario.