I get all my upholstery done by a great company in Germany. Interieur.
They have supplied me with all the right stuff for years. no task is too big and they have all the patterns for almost every glider.
I am not affiliated with them in any way but have known them for 25 years

https://interieur-albstadt.de/interi...-albstadt.html

The carbon sticks are also great. I still have one here, but I would need to check the internal diameter to be sure it will fit a libelle, but I am 99% sure it will. If anyone is interested...

The Libelle group that is very active is he

https://groups.io/g/libelle/topics

Great bunch of guys that are always willing to exchange info and help out where they can.