Heh, I feel your pain because my backstory is very similar. The only difference, I think, that the previous owners simply did a lousy job installing the irrigation system as it’s been in place for years. Just the other day, I found a leak in a cracked PVC pipe that they left exposed on the surface. They used this pipe to extend a lawn zone to water trees. How do you like this beauty:
My plan is to eventually segregate as much as possible by plant type. I’m going to use this opportunity to move the trees from the lawn zone to another nearby zone that has only trees and shrubs. Then I’m going to convert that entire zone to drip (it’s on bubblers now). But I too have a hard time understanding how to make Rachio work with GPH of spot irrigation instead of IPH of wide area coverage. I’m watching this recent post: Struggling to get settings right for drip - Schedules & Zones - Rachio Community hoping that someone will chime in with good insights.