It is of course necessary to verify in advance that a given instructor is accredited by the issuing authority for the County or city in which you are applying - it sounds like everyone is tracking that but worth making clear to others who may read this thread in the future.
I've done all my work through Leo Defensive Concepts and highly recommend them:
https://www.leodefensiveconcepts.com/home
Leo Defensive Concepts is accredited in Alameda County, and work mostly out of the Livermore - Pleasanton Rod and Gun Club, located North of Livermore CA. Most of the instructors are former law enforcement with important insights into both practical and legal aspects of carrying a concealed weapon. They are attentive to students, ably passing on lesson material and focused feedback for improvement.