I think this is a great topic, even if you weren't doing it to select a spot to take someone.
From my limited experience, the Underwater Park would be great earlier in the spring. My first 10 dives were there, and the las times I went all I was doing was swimming across an endless salad bowl. While it gets mention in every magazine article about the area, it's best when the kelp is at it's lowest.
I'd recommend going just a few blocks farther and doing the Oil Dock. First dive I did outside the park, and my best dive ever, even more so than the wrecks on my OW cert dives. Tons, literally, tons, of ratfish and sunflower stars, and if you have the benefit of sunlight, it's amazing to be under the dock swimming through the pilings. There were schools of shiner perch, tubesnouts, and oh, did I mention the ratfish? If you don't get a chance to see a six-gill, there's always the chance to see a dogfish there as well.
Of course, I'll be diving Sunrise for the first time this Saturday, so my opinions may change.
gomi_