Um, basically the above holds true, the west wind brings in the warmer and cleaner water, but can make it surgey...While the east flattens it out, makes it cold and dirty....Usually for the heads (Paquita) you can dive on a west wind, even if the sea is big...Not at coney glen, if the heads is breaking or even got a bit of a chop on it then its surgey and white.
I went for a dive on the paquita late yesterday afternoon on the Low Tide (Prefer the hide tide) and had about a 3m vis. Bear in mind that you cannot spearfish within 30m of the paquita, so just to dive and practice it wasn't bad conditions.
Maybe some of the other guys can give you more advice on the weather conditions that are prime, i usually look at how flat the sea is, then look at the colour...If all looks good then i get in and go hunting.