open hardware... unicycle seat cover pattern?

Hi,

Covers of unicycle saddles will -over time- wear out.

I’d like to have backpack prototyping design company make it for me, who also made countless bike-bags, and have many very nice materials.

So I wonder, to get the best fitting pattern…
The seat I’m using is basically a Impact ‘Naomi’ (but with “Axel” carbon bases).
Is there something “open” out there, or should I better use reverse engineering?