I am well pleased with mine came in handy tonight whilst rebuilding a regula 25 cuckoo clock for
checking pivots. I have a balance spring to sort out soon so again will be in use a useful tool when you consider a bergeon hand gauge is nearly £40 .
It would depend upon how the strap attaches to the case. Based on what I can see, my hope would be that you can remove the caseback and then slide the band off with some kind of tongue and groove fitment. If that's the case, my inclination would be to 3D model a piece that would slide in as an adapter and can accept standard bands with springbars and then 3D print it. Once you have a design that works, send your design off to one of the places that can 3D print in metal to have them create a more attractive and durable long-term piece.
A couple that does Youtube videos on making stuff called "Evan and Katlyn" went through this process in a series of videos a few months ago for making a custom folding knife. They have lots of guidance about the process in those videos.