I usually spot on the intersection of Curlew and Union Streets (Coordinates: 32.72903° N, 117.16767° W). I have also heard of some good parking structures such as the Aladdin Airport Parking which are also good for spotting.
I rarely spot in San Diego so those are the only two places I know to spot, but I’m sure there are some other spots that are much better that I’m not aware of