No worries Lizardmen, I'm not that much better and I have ZERO power mods to the VX. I get basically 16-17 mpg, if I get 18 I'm thrilled. I have no dreams of getting 20 or above. I don't know how some of these other guys do it. Yes, I use constant throttle pressure, very limited brake action, always in 4th when I can help it, rarely goose it around traffic and my mileage still stinks. Oh well, I knew gas mileage was one of the faults with the VX. At least we get to use regular gas!
The only thing I can think of in your case is to make sure the tire pressures are good, if one is really bad or more than one are kind of bad, that would be a cheap and quick fix to your problem. Especially given the large size of these tires. Good luck!