The key items are annoying because in some cases there are multiple flags that need to be edited just to get a single item to work. The Celestial Mirror, for example, requires 6 flags to be edited. One to get it to appear in the menu, one to make sure you don't get the Cloudy Mirror from the race, three to complete that sidequest with the family in the woods, and one to let you actually use the Celestial Mirror. Primers require two flags, one to get it to appear and another to get it to actually do something. It's weird.
For equipment, it goes like this:
-2 bytes for the name
-1 byte to say if it exists or not
-1 byte to signify special properties (for celestial weapons and Brotherhood)
-1 byte for the character it can be equipped to
-1 byte for type (weapon or armor)
-1 byte for who it is currently equipped to
-1 empty byte?
-1 byte for the weapon damage formula
-1 byte for weapon attack
-1 byte for the weapon critical hit percent
-1 byte for the amount of Auto-Ability slots
-2 bytes for the model that the equipment uses (what it looks like)
-8 bytes for the Auto-Abilities
This is what the Masamune looks like, as an example:
http://img14.imageshack.us/img14/6904/equipdata.png