Given the huge investment of such an orchard, I suggest easing in and not going straight to Flex Daily-type schedule so that you’ll have time to figure out the why’s and how’s of irrigating a fruit orchard. You’ll want to stick with what you know works via a Fixed schedule until you figure out the details of using smart irrigation and understand how Rachio’s smart features work.
If you have an unused zone, that is not hooked up to any sprinkler valve, I suggest setting up a test zone to learn how Flex Daily or Flex Monthly works based on some basic fruit tree centric settings. Learn about Saturation skip for Fixed schedules. You’ll want to work through that drip spreadsheet to at least determine your precipitation rate based on tree canopy diameter and GPH of emitters at each tree. You’ll want to do a little bit of research on root depth of your trees. You’ll want to know, at the very least, what the summer and winter crop evapotranspiration coefficients are for your trees — there’s lots of UC Extension documents on that. You’ll need to know about the Available Water Capacity of your soil. You’ll want to find a weather station that is near you and reliable for rain gage data. Keeping a log of all this information you collect would be ideal—and keeping a log of your tree health, status, etc., would also be important especially to monitor how the trees react to a change in your irrigation regimen. They might not react favorably… as has been the case for me a couple of times and the only way to know is monitor tree health almost daily for the first year of a new schedule.
Anyway, I cannot offer any instant tips as it’ll take research, vigilance and adaptive management to protect your trees. I would say keep the trees on drip and see that the emitters aren’t right up against the tree trunks (they should be positioned closer to the driplines). If they are ponding, reduce the # of emitters so that the soil can keep up but lengthen the watering time accordingly (if using Fixed schedule, you’ll have to lenghthen watering time manually. If you use Flex, removing an emitter would change the inches/hour precipitation rate (which you’d change in Advanced Settings) and Flex would automatically calculate a new watering time).
Post on calculating precipitation rate and finding your soil’s AWC (a good start/primer; has really good introduction text and I pilfered the formula to calculate in/hr for emitters at my trees using my own spreadsheet):
My favorite crop evapotranspiration tables for California:
http://www.itrc.org/reports/pdf/californiacrop.pdf
Hope this helps. It’s a journey of learning but is worth it! Ask questions at any time — we’re here to help every step of the way!