One of the things to remember is that the Sheriffmuir is in effect a two part garment, usually worn with a high cut waistcoat (six button), usually round neck.

A full jabot will cover and hide the top of the waistcoat. A stock, bow tie or a cravat will not.

A Sheriffmuir can be worn without a waistcoat or with a three button waistcoat, but doesn't that defeat the object of wearing a Sheriffmuir?