Not DIY, but the kilt pin I just purchased for bigdad1 (see his avatar) is a large, heavy piece held w/ two tie tacks, one each top and bottom. They are a higher quality than the ones you show (the removable part aka clutch pin is a solid piece, you pull the end up to release vs. the "pinch and pull" you show). Worn on wool, I might be concerned about the "pinch" mechanism snagging fabric. If it's on demin or the like, I see no such issue.

Interesting find and it'll be fun to see the finished project!