Which model gets best MPG, 5 vs. 6 speed?

[dsinned_imp]

This is the first motorcycle I've had that I can cruise along on the freeway - absent of any traffic congestion, of course - at a leisurely 2500 to 3000 rpm in 6th gear (55 to 65 mph). Frankly, it's hard to use my poor man's CC, because the throttle is barely off the stop. Although, I only use CC to give my wrist a break every so often. I'm certain my fuel economy would easily top 50 mpg, if I rode like this most of the time. Unfortunately, I live in a large city with over 1 million people, so freedom to ride at the speed limit, other than after dark, is sadly a rare event.