I'm just commuting about these days.
So I just ordered up a 50 and 47 tooth sprockets, new unbent bars, maxxis promaxx m6102/m6103 street rubber (they are crazy cheap at bikebandit and the customer reviews rated them as equal to the BT45.) and of course wheel weights and a pair of spoons.
Note: The Maxxis site says M6102 comes in 3.00-21 as does motorcycle-superstore, bikebandit has it listed as 90/90-21.
The 50t should give me a 9.1% drop in rpm or a 10% gain in speed, however you wish to view it.
The 47t should give a 14.5% drop in rpm or a 17% gain.
A 44t would give numbers of 20% drop or 25% gain, verses stock 55t
Shifting from 1st to 2nd is a 26.5% drop in rpm or a 36% speed gain.
I feel that 2nd gear with the stock 19/55t is borderline for taking off,(as I don't want to put excess wear on the clutch) so I stayed away from the 44t feeling it would make the new first too close to the old second. Also I like the quite stock muffler more than my supertrapp and pulling 6th with the 44t may need the assistance of the trapp.
Actually now that I look at my numbers first gear with 19/44 is nearly identical to 2nd gear with 18/55. (And 18/44=19/47 or dern close)
5th->6th shift is a 14.7% rpm drop or 17.2% speed gain.
Tune in in a few weeks for the empirical info.