Chris Mills was my instructor in 1974, at which time I learn to fly hang gliders in the Gatineau Hills north of Ottawa Ontario. Chris and I both went to the same high school. Later, he moved to the area near Guelph Area and continued to fly hang gliders for a number of years. Here is a shot of him launching his Delta Wings Phoenix 8 off the top of the Georgian peaks ski hill, overlooking Georgian Bay in Lake Huron, in 1977.
As the aspect ratio of hang gliders increased from the basic standard rogallo design, gradually the length of the leading-edge tubes also increased and it became harder to keep them straight and not flex with slight loads. At that time, manufacturers used fairly small diameter tubes, perhaps 1.5-1.75 inches. Little stays and bracing cables were installed along the leading edges, called deflexors. If you knew what you were doing, you could actually tune cable tension differentially on each one of the deflexors in order to get rid of a turn in the glider.