I throw my housing and domes in a padded cooler bag which you can buy a Big W or K Mart for $25. Wrap them in a few layers of bubble wrap and have them weight in under the 7kg carry-on limit. Good thing about it is that you can use as a camera bag for carrying to and from the dive sites or on a dive boat.
I decided to take Adams advice and shoot with AF-C and with group points (4 in a diamond shape) with my 10.5mm Nikor Fisheye on Grey Nurse Sharks at Fish Rock, South West Rocks, Australia. Over 5 dives and 1700 odd shots I only had 2 shots which were out of focus but mind you I was shooting inside a dark underwater cave at the time. Interesting as it was in a 4 shot sequence one shot was in focus then another wasnt and number 3 was in focus and number 4 wasnt. But overall I was happy with shooting in AF-C.
I found the best spot to be near the feeder and on the side which he feeds from as you want to get the action shot of the shark coming in and grabbing the bait and then moving towards you. Practice shooting with higher FPS to get the action shots with strobes turned down to keep up with the camera
I dont shoot macro very often but when I do its like 3-4 long dives a day for several days and normally in Indonesia. Last trip I bought a Tokina 100mm macro lens and used this for the whole trip and used with the Aquatica close up lense (+5 and +10). The reason why I bought the Tokina was because I didnt want to spend the money on the 105mm when I dont shoot macro often. I was surprised with the quality and performance of the Tokina 100mm macro. The AF was super fast and pin point accurate and there wasnt a need to go manual. There was some very fine rocking back and fro when using the +10 but this was in only a few rare occasions during the trip.