Quick suggestion for you, it might be an idea to add more at the start of each act as well. I have a few mods that add items for player ease-of-use and usually a few people who haven't got the item yet later in the game will pop up and ask for later-act support.

As a note IF you do this, adding items to the ship can sometimes bug the ship out, so usually near a waypoint or at the start of the act on land would be potential candidates for them.