Enjoyed your report; fine job! Glad to see California get more attention as a tourist destination; it's worth flying to to dive. Interesting your decision tree. Like me when I went, you wanted to try a different environment (e.g.: cold, kelp/plant structure rather than corals) with different wildlife (including marine mammals - I'm jealous about the sea otter!) in a different ocean.
But I chose south later in the year, when/where it's warmer, and also cold-tolerant got by with 5-mm wetsuit & gloves, 7-mm hood & boots, and chose the live-aboard route (housing, food, transportation, lots of diving all rolled into one, and boat diving's easier) and the Channel Islands were billed to be amongst the best. Chose Southern Channel Islands for warmer water. I love shore diving for the dive freedom it offers - any time, any site, solo okay. But I can't spend the time in California it'd take to get proficient enough for solo shore diving there, so I figured it'd be a more work and less diving.
You headed north (colder), earlier in the year (I'm guessing colder), did shore diving (more work, fewer dives, and probably not particularly cheap since guided though you got valuable service)...a different approach. Glad it worked well; planning my trip was tough - California offers a lot of options.
You mentioned 100-cf tanks. When I went, 95-cf seemed to be the biggest commonly available. Given the higher gas consumption in some cold water divers, and the use of dry suits that require gas, I got a question...
Why aren't 120-cf steels are more common rental option in California? I found them at North Carolina (Olympus Dive Center) and Jupiter, FL (Jupiter Dive Center). Seems like California lends itself to big tanks.