...And if we do this route, how far should we surface swim at the beginning before dropping down?
The further, the better. One thing about Point Lobos, if you don't have a boat or scooter, be prepared to do some surface swimming. Stay parallel to Cannery Point, then sink down before you start getting to the rocks. If you're going to do the square pattern, I'd save a little more gas in case you need to swim under the kelp in Middle Reef.
There's a LOT more kelp here than in Laguna, so keep a lookout. The stipes and holdfasts are quite a bit bigger here, too. No lobsters though. :depressed:
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