Sounds like a plan. BTW I returned to GC in 2009 with my family after a 27 yr hiatus and thoroughly enjoyed it. We all dove. I dove 2 tank am boat dives with DT and then the family joined me for shore dives in the afternoon. DT runs a good dive boat and are organized.
GT and 7mb is much more developed since your last visit but you can still find parts of the island that have that old GC vibe. Enjoyed the shore diving at Turtle Reef with the obligatory post dive cracked conch appy and cold beverage. Ollen Miller and Sundivers on site are friendly, efficient and have a nice set up. We also enjoyed shore diving at Lighthouse Point and Eden Rock. At all three places, once you have the initial paper work/releases done, repeat diving is much faster. My family enjoyed the shore diving and we have been back a number of times since, the last trip earlier this month.
Enjoy.