I don't have any doubt that Sunny has used this with success on murray cod. The only question I would raise (and Sunny, you might have a look a couple of the rigs you have used as I am interested too) is whether the FG you are tying on the fluorocarbon is effectively biting into the leader. If not, you may find that the knot is actually largely reliant on the burnt knob at the end. This is akin to placing a brick under the front tyre of a car facing downhill. It will be fine but if you start pushing behind it, at a certain amount of force, the car will go over the brick. Obviously, if you had Mini-Me pushing it, nothing would happen but if you had Andre the Giant, it might be a different story. I supopse we could draw the same analogy between Mini-Me and Andre the Giant as between a small coral trout and a big GT.