My favourite place for a kilt pin is in a drawer somewhere!

Sooner or later a kilt pin seems to get caught on something and tear the kilt a bit. Look at a pile of 20-year-old band kilts from a band that wears kilt pins and you won't see many that aren't torn.

Anyhow in this matter as in so many others what the Army does is what looks "right" to my eye:



I like a pin more or less halfway between the bottom of the kilt and the edge of the jacket. They always look odd to me when pinned at the very bottom edge of the kilt.