Maybe this is an idea...

A 1" badge is big enough...as a badge, but it's too small to stand alone as a kilt pin, but when you attach it to a "background" pin it will look great.

Maybe a standard clan crest sword pin...remove the clan crest (with some respect) and attach the badge to it. Other kilt pins can be used also of course.

Drill a small hole (or 2?) in the background pin, cut the pins on the back of the badge to 4 or 5 mm. Use 2 part epoxy glue....done.