I would suggest smoke treatment and then sowing at this time of year. It germinates in habitat in fall with the start of winter rains, and usually in response to fires, and San Diego climate in winter should be ideal. Also, be careful with the ph and water quality issues, as it is probably only suitable in more acidic granitic/sandstone soils in your area, near to the coast. If you live near protea farms or avocado farms, and well drained coarse granitic soil, you probably have ideal conditions. I would be very careful with irrigation if your water supply is Colorado River water.

I start to germinate them with the smoke treatment, hot water (about 50C°), and keep them warm for a day in the smoky solution (25-30C°). Then I put them into the fridge in wet perlite (with some fungicide) for a month. Check them every weekend, and let them sometime to warm up a little bit. They germinates after four weeks (it is nearly 100%). It works for the proteas, not nut-like seeded leucadendrons and banksias. The seeds should be fresh.