This is a model I made 3-4 years ago …
I think the binds in our house are from the 90's (they were here when we bought the place and we haven't changed them yet). Some of the valence clips started to break, likely from age. So I found one that wasn't broken and traced it onto a piece of paper, scanned that paper in, and then sketched out the contours.
I think all of the old valence clips are now broken and I'm only using 3d printed ones.
We'll replace our blinds at some point. :-)