I have been doing some checking with regards to gearing.
My GSF1250SA manual specifies the final drive ratio as 43/18 (2.388 ratio).
I have not yet counted the sprockets to see if this is what is fitted to the Australian bikes, but it sounds right as Holeshot goes a 17T front for better acceleration.
Vortex Racing sells Bandit Fr Sprockets in the 14-18 tooth range and Rear Sprockets in the 38-53 tooth range. (Listing for GSF1200. Probably the same fit. Anyone confirm this?)
Removed the cover from the front sprocket. Clearance between the gear teeth and the rear cover bolt spigot(?) is pretty close (approx 1/8 inch, by eye...
), the clutch pushrod is also pretty close. So fitting a 19 tooth sprocket, if you can locate one, may end up being tricky.
Looks like -3T on the rear and shortening the chain may be the way to go.