San Diego is 10 hours behind Addis Ababa
There is no standard 8-to-6 overlap. Someone joins early or late.
Given San Diego is 10 hours behind Addis Ababa, the realistic answer is that there's no convenient shared slot during normal business hours. Catch the edges of the day: the last hour for Addis Ababa or the first hour for San Diego is usually the least painful option. The window above shifts seasonally: San Diego keeps daylight saving while Addis Ababa ignores it.