Is this the Chevy LS1 engine? If so, it looks like it would be an easy swap to move the injectors over on this cylinder and its adjacent cylinder. Have you done this yet, just to see that the misfire stays with the cylinder you have measured in the Pico trace?
I put a 1kHz low pass filter on your trace, just to make it easier to see whatever the WPS transducer was saying. The manifold pressures on both sides of the cylinder look pretty healthy. The valve durations look a bit short; I think that the LS1 engines available this side of the pond have inlet and exhaust durations of 200degrees apiece, with hydraulic tappets and roller followers. If all else failed (all the easy fixes, like fuel injector checking, and scoping the secondary currents near the plug), then it might be worth checking valve lifter gear for wear on this cylinder.
I have a RangeRover 3.5l V8 that I have given up trying to diagnose the intake/exhaust profiles from the WPS; it just gets to the point where a spare engine is quicker, once you know you have to strip down the whole unit!