Just an aside, I am definitely opposed to the 'modern' practice of wearing kilts low, but re waistcoat length it's not exactly correct to say that waistcoat lengths getting longer is a departure from traditional highland styles - there's plenty of images that illustrated longer waistcoat lengths were also acceptable - indeed quiet a few that illustrated at certain periods waistcoats typically worn by civilian Highlanders were actually longer than the jackets worn over the top.