Hi, it is great to get to th grand cayman! we dove the stingray city by ourself anchored not too far away, it is a must to see but you are not going to be the only one around! The north wall offers a lot of nice dives and is less crowded than the south side. We dove princdess penny's wall, tarpon alley west and east, eagle ray pass, blue peter reef, ghost mountain, chinese wall... all are beautiful and visibility gorgeous when we did it.
We stopped the cayman islands arriving from saint martin (FWI) and we found it the only place until now where they let you dive from your sail boat just using the buoys. Here it is just first show first served, eventhough you are not a dive op!
If you dive the north wall you'll have a bit of transportation to get to the other side where the dive shop is probably, and cruises ships arriving in cayman are more than one!!! we had about 7 cruise ship anchored or on engine all day just behind one of the 4 buoys for sail boat to moore and stay in kman!