Wearing a long tie with a kilt is a little challenge for me. In case I am not wearing a waistcoat, I like the tie to end above the top of the kilt. Moving the body of the tie up, making the small (back) end longer puts the bottom of the tie in the correct place. Then I deal with hiding the longer back end. However, being a fan of bow ties, this is often my way of avoiding the tie length problem.