This is so subjective, here's what works for me, others in the colder north mostly seem to fall on the SG side of the question. I quit using SG when topping w/a good wax and would skip it in your case since you're in SO CA.
Here in GA, with garaged cars, I don't get any benefit from SG that I can notice. The initial gloss and pop is gone after 7-10 days with AIO-topper looking just as good with the topper as AIO-SG-topper, and durability hasn't been a problem for me as 3-4 months is all I go without polishing again.
I do top with wax every 45-60 days, after regular washing. I use P21S shampoo and believe this has something to do with miniminzing marring, giving a just waxed look each time, and getting good durability (at least good enough).