When someone wants to add a recipe for a custom chestplate, he needs to manually assign ingredients to these 8 slots. It would be convenient if there were quick templates for common shapes like helmet, chestplate, leggings, boots, swords... For instance, there would be a separate menu for adding a sword recipe that would only require the user to select the stick material, blade material, and the output item.

I added the crafting recipe templates and pushed the changes to master. It should be included in the custom items 8.1 release.