Cheap Ebay Spool Masterspool Upcycle

A long time ago I bought very cheap filament off ebay. After i finally managed to get rid of all the filament (1kg) I had the spool as a leftover.

Today I buy my filament from dasfilament.de and I want to use the refills in the future. I dont want to print the entire masterspool, so I decided to try myself on a way to upcycle said old spool.

Old spool diameters:
Outer: 200mm
Inner: 78mm

Refill Diameter
Outer: Does not matter as long as it is under 200mm
Inner: 102mm

I drew a thin