It sounds like you have the weathered MacDonald of the Isles Hunting:


There is a thread in which Barb mentions how to hem a kilt, and using it my mother (who is a much, much better sewer than I will be) shortened one of my kilts by about two inches, creating an invisible hem). Do a search for "hem" or "hemming" and the thread should pop up.

Good luck with the alterations.