I probably get about 80-90 miles to reserve on mine.. now I also am a largish person (280lbs). I have stock jetting and exhaust, but ear shaved.. I ride about 4 miles each way for work, with some occasional running around town.. all in traffic, with speeds this time of year rarely exceeding 60 mph.
I fill my tank to the bottom of the collar just as you are.. your not gonna fit much more in after you reach the collar.
Now, on the occasion I can get out and ride for some distance, my mileage goes up to 100+ before reserve. its all about getting the mass (bike and rider) moving.. takes a lot to get us larger guys going.