As a storyguide I would probably present this as a challenge to players and as flavor in the Order. Since you could probably generally just add requisites (though maybe an extra magnitude in certain cases), the magi making the items will probably use requisites that are their strongest other Arts. So, for example, if several magi make an item to spy on an area (essentially the same item) you might get:
- A painting that changes its image to match what is there from a MuIm expert.
- A slab of stone that molds itself to match what is there from a MuTe expert.
- A mirror that displays an image of what is there from a CrIm expert.
- A knife that carves an image into what it's placed on from a ReTe expert.
That you could get so many variants and that the variants would tend to suggest something about the creator is fun and adds flavor.
Chris