How can I calculate the following:

# units / mth, 2 units produced evenly scheduled throughout the month, only
on weekdays

6 units - Jan (resulting in 3 schedule dates)
4 units - Feb (resulting in 2 schedule dates)
5 units - Mar (resulting in 3 schedule dates)

How would the calculation be modified to schedule 1 unit evenly throughout
the month?

Thank you in advance,
Janice