yeah. goes something like this (ill most likely skip a step or two):
-use w-item skill
-use an item on you or your party, etc.
-second item, use item you wish to dupe, it will bring up target cursor for who you wish to use it on, you cancel the window, and gain 1 more of that item
-repeat.
im most likely wrong. lost my VII game, so i cant figure out how it went again.