There are a number of grass or lawn zones, and three for beds front and back as well as one for a river birch tree. I am not quite sure I follow your explanation but I was hoping for a check box to enable the Monthly Adjust plugin for each zone.
It is not just the amount of sunlight hit the lawn that counts, although this is very important. Attached is a link to a pdf file from the North Carolina State University explaining turfgrass watering needs http://www.turffiles.ncsu.edu/PDFFiles/000851/ag661.pdf . I realize that you may not live in the Carolinas or, indeed have turfgrass (Tall Fescue in my case). What it does show is a nice set of numbers and an explanation of how to look at soil water retention.