Squid are found everywhere. Rivers, lakes, beaches. open ocean... Jetties and rock ledges are usually suggested simply because it is easy to catch them there.

I don't think tide and solunar cycles affect squid. But you could use the Solunar clock and keep a diary to find out.

If you have been reading up on it, then I bet you are using squid jigs and actually jigging them ? Nothing wrong with that, it works. What I do when I am targeting squid is slightly different and works very well.

I use a bobby float with mirror sides. A simple rubber float stopper allows for quick and easy depth changes. The squid jig is tied direct to the line under the float. Set the depth to about half the depth of the water. Cast out and just leave it there. The movement of the water will make the jig bob up and down and the light reflecting off the mirrors gets the squids attention.