Thanks.
The ceiling hooks I used are all installed with fairly heavy duty anchors, rated to carry weights that give at least a 4:1 safety ratio. The heavy-duty fishing line I used has a similar margin of safety. Each ship is also strung to multiple hooks, just in case. It all should last fairly well.
We've used a fully modular shelving system, with full length vertical mounting strips (eg,
these), so that we can adjust any shelves if we need to reorganise or fit more levels in. Elfa is the deluxe brand of the system of shelving, but Mitre 10 and Bunnings also carry a cheaper Australasian brand called "Top Shelf".