Hey @Alx - just wanted to acknowledge your generosity in being able to help the owner with his trees and also acknowledging the difficult in learning how to water. I panic when I think about taking a trip in the summertime for a few days and how to address my collection. I’m sure the owner was thankful to have someone to step up and help. I think you got a lot of great advice on this thread - watering is so essential to these trees but it takes a lot of experience to understand the signals and information that they are giving you.
I’m well over 10 years into this hobby seriously and still have issues related to watering more than you’d think. We all make mistakes and flubs no matter what level of experience we have. Hopefully these experiences here will give you something to reflect on and help to deepen your knowledge of watering and overall plant health.