The wide belt is what I have seen referred to as the "French Style" belt; which evolved on the very early planes that did not get into the aerial antics of later aircraft. The more research I do on WWI planes the more I learn that anything is possible; and that things evolved very quickly to suit individual pilots. I have come across at least six variations of windscreens for Camels, they all existed and are all correct for that plane. I am sure there were field installations as well to suit a pilot's particuliar needs when it came to seat belts as well. So in my mind both could have existed at the same time; as well as other variants.
Personally, I think the wire with the pullies was a field installation that may have evolved over time to a later factory installation. The same thing still goes on today with military aircraft in the pursuit of an edge and improvement.
Ken
