I fish mainly middle harbour and I got a decent spot for you, middle harbour is virtually full of squids but a good spot you can try is one of the wharves at the spit on the left hand side when coming from Mosman towards the northern beaches, you’ll also find them anywhere around the spit marinas and the bridge. You will find squid are at Most of the jetties and pontoons Aswell, and there’s one more which I can tell you 😉 just don’t want it to get overcrowded.