@davelr, great question. I'd recommend creating a schedule for each of your vegetation types; i.e. if you have 5 zones with cool season grass and 2 zones with shrubs or trees, create two different schedules.
Similar to Smart Cycle, we base the schedule intervals on Flex Monthly schedules based on the most sensitive zone in the group. For example, if you have a grass zone and a tree zone on the same schedule, since the grass zone as a shorter root zone depth, it will need to be watered more frequently. As such, the tree will be watered at the same frequency as the grass, but for shorter durations.
To better understand how crop coefficients impact the schedules, please reference this support article the table below (taken from the Flex Daily FAQ, but the same principals apply):