I found that Ocean Frontiers between Gun Bay and East End rents tanks to take off site. Definitely will try to get some boat dives in on that side of the island but we always enjoy fun and challenging shore dive opportunities. We do have two kayaks that could reduce some swims a tad.
When hit SMB the following week, planning to hit the typical shore dives - Turtle, Hepps, Cobalt/Dive Tech, Cheeseburger, Eden Rock, Devil Grotto, Soto, Sunset, etc, etc.
I suggest boat dives when you are on the Northside to dive the East End, and then some shore dives and maybe a few boat dives when you move over to 7MB.
What time of year will you be visiting? It may get windy on the North Wall in winter and the shore dive at Cobalt may not be available at that time of year.
There are a lot of good dive ops that service the 7MB area and most will pick you up by van or by boat.
Try to avoid the George Town shore dive sites while the cruise ships are in port. Hepps is available as a boat dive but they recently ruled that only guests staying at Coconut Bay can shore dive the site.
If you have never dived stingray city you should do it at least once, but again avoid the busy times when the cruisers are around.