Multiple Controllers Decent Size Property

I’m currently running 12 zones on a Rain Machine controller, 9 zones of lawn and 3 drip zones for trees. I’ll be adding in 9 more zones for my lawn and 2 zones for a garden and eventually a couple more zones for landscaping. This would require 2 - 16 zone units. I’m also on a private well so I have to make sure only one zone at a time runs.

So with 18 lawn zones, 3 drip zones for trees, 2 drip zones for the garden and a couple more drip zones for irrigation, how do I make use of the flex daily or monthly schedules? To add in another stipulation, I would prefer it not to run during the hot afternoons and the evenings when people are around.
Does one controller get certain days and the other controller gets the other days?
Or one controller gets 10pm-4am and the other controller gets 4am-10am?
If you limit controllers to either certain days or hours of a day, will Rachio water fewer zones but give them a deep water and slowly cycle through all the zones as it can or will it try to water all the zones that need watering and cram them into the days/hours allocated even if that means cutting the watering time down? I definitely prefer the deep watering’s, most my zones currently run 1-1:40 twice a week and that seems to work.
What are viable ways to set this up to run efficiently?

I use start before and start after watering for two controllers. I use Flex Monthly and have one grass schedule and one flowers schedule for each controller. The Rachio controller doesn’t modify watering time to fit within a time period so if you run both on the same day one unit needs to be set to finish by 4AM and set the other too start after 4AM. Depending on how many zones need to run the one may start before 10PM and the other may end after 10AM. My units don’t have any overlapping turf zones so it doesn’t matter if the front yard waters one day and the back yard another day. I would keep all overlapping turf zones on a single schedule and not do flex daily as the overlapping area will be watered unevenly than the areas that don’t overlap with the next zone. Also for simplicity make sure that you have separate common wires for the two controllers. If you share a common you have to add isolators which there is diagrams that can be found in the forum.

I just set up 2 8 zone controllers. I set up 2 Word doc tables, one for each controller. In one column zone, next area, then how often and how long I wanted the zone to run. And the last column the schedule.

I then set up another table for the schedule. I set up this table with the schedule name including which controller, type of schedule, zones in schedule, time for zone, And the last column was when I wanted it to run. This way I could be sure no two schedules would overlap. I then went back to the zone table and entered the schedules. And finally taking the table for schedules programed each controller.

One of the things I read earlier was that if any schedule over laps another schedule the second schedule may not run. So I set my schedules with enough time between to be sure no over lapping.

In the house I sold If any zone schedule overlapped another then the 2nd would not start until the running zone completed it’s schedule.