I've messed with it. Got more out of timing then that screw. Just a waste of time and fuel backing it out. The fuel screw helps to a point then it also just becomes a waste of time and fuel. If I weren't tired of working on other peoples big trucks I'd turn mine back down and experiment where I get the most gain and least smoke out of my fuel screw and set the torque screw back to where I found it.
Pretty beat subject if you haven't noticed, like zf conversions, twin or bigger application pumps, big turbos, more power threads.