You have hit on what is, for me, the single most unsatisfying aspect of owning and riding the R3T. (I know you have a standard - but I think these issues still apply)
First - It's d*mn near impossible to fuel the Beast up properly. The Owner's manual says to fill it to the bottom of the internal filler neck, to allow for expansion and prevent overflows. Well, if I fill it to that level I CANNOT get the rated 5.9 gallons into the tank. I need to fill it to just under the top flange in order to get 5.9. I have no idea what's going on with this. And with the higher pressures being delivered by today's gas station pumps - it always cuts out long before the level I need. It sometimes takes me 8-10 minutes to fill the tank - If I can fill it up all the way at all!
Second - I cannot (and never have) obtained nearly the mileage reported by Boog in his post above. I've installed a tach on my R3T and find that 3,00 RPM is about 78 - 79 MPH. At that speed I'm fortunate to get 33 - 34 MPG. In town, I'm often below 30 and when I encounter the occasional traffic jam - I can be as low as 25. I'm running TORs with an underseat K&N and Triumph's TORs tune. I haven't been able to find anyone to assist me in installing Wayne's R3T tune, which promises not only 115 hp but 40+ mpg - but I'll keep trying.
Third - If I want to get 200 miles on a tank of gas - I'd better be going 50-55 MPH steady speed - under those conditions I've accomplished that 2 or 3 times. The"range to empty" feature works poorly. On at least one prior occasion I've ridden nearly 12 miles with it on "0" - and I still had some gas left. I never really know how much gas is in the tank or what I have left.
I would simply resign myself to the fact that a 2.3 litre engine with 3 - 4" slugs is never going to be a Mobil Economy Run champion - but then I see guys like Boog who get these incredible mileage figures and I'm simply at a loss to figure it out.
I love the R3T - but I absolutely hate everything having to do with fueling her up or the gas mileage.