charlie. what your trying to do is possible, but it can be made more simple.
If you might be able to suffer through providing a few answers to a few questions, a few times, im sure we can provide an ultimate answer.
First, in your post, the minutes are not assigned to a season, should we assume the minute per zone are the same regardless of season?
Second, why must zone 6 run at such a remote time of day from the other zones?
(if your to omit an answer to these, the first question is more important the the second question is less important)