Dufty has always been a great attacking weapon- he played in the halves as a junior and so the passing game was always there- where he needed help from Flanno (and still needs it) is confidence in going for the high ball, positional play, strength to resist the "rag doll", communication with his defensive line, and- critically- defensive technique.
i remember reading about the great full back Clive Churchill who was no bigger than Dufty. Part of what made him such a great player was his reading of play in defence. For example, he understood that when a big player made a break and was bearing down on him, he was at a disadvantage just standing there waiting to be crunched. Where possible, he would rapidly close the distance between himself and the attacking player so that the attacking player's footwork was disrupted, thereby making him an easier target.
The old saying is that defence is all about attitude- but it's also about technique- and that comes naturally to some (Jake T) and not others.
I've given up on Dufty at FB because he causes more problems than he solves. Att 5/8 he can get some help from his forwards with his defensive responsibilities. I'm on board the JAC train for full-back if we can manage to give the Storm say Saab and some cash.