Which would use less fuel?

[CaptainHenreh]

WOT is the most efficient, 5th gear would be the lowest RPM so I vote 5th gear.

+1 Fuel is added by throttle position, RPM, and load. (otherwise you wouldn't need a MAF/MAP, just a TPS) WOT=Max volumetric efficiency.

You want low load, low RPM, as much throttle as possible.

We've had this discussion on MM before, I think. The consensus, IIRC, was RPM's as low as possible, as light a load as possible, with the throttle as wide as possible, without lugging the engine.