Several years ago the position was called FCTI (Flight Crew Technical Instructor), which was a combination of SFI & Ground Instructor. As far as I know they had a FD06 Grade, which reflects about the Senior FO grade and package (housing, travel etc.) and three bar epaulets and no wings
(as TCAS would not allow for it).
Some guys made a good career out of it; the now retired Dutchman comes to mind, knowledgeable Gentlemen and a well respected member of the pilot/ trainer community.
Maybe someone else has more up to date information.