A Calligraphy toolkit seems like an odd fit into the game since such a thing is intrinsically a superfluous thing. It isn't just used for a scribe as a quill and ink would be far easier to gather since the quill could be gathered freely during the molt (most commonly from a goose but crows, eagles, hawks, owls, and turkeys are also used) and then only the ink would have a cost.
It stands to reason then that the Calligrapher's toolkit is going to be as much a decorative as functional item. This kit is a representative of both the Calligrapher's skill and their accomplishments. So the box itself will be something special, lined with decorative fabrics, and hinged with wrought metal (perhaps silver?). The pens themselves will be beautifully carved and blown to present the Calligrapher with a utensil for their craft that speaks of the elegance of their craftsmanship.
To be a Calligrapher is to be in a luxury profession where the richest nobles call on your services and even the lowliest scribe rolls their eyes in your wake. For that reason I can only imagine such professionals to use a box as beautiful as the Windsor Prose Writing Set (pictured above). It's a good benchmark for what the sets your Calligraphers use should look like and feel like.