, I see you didn't get very much in the way of valuable responses for whatever reason, but I'm interested in this as well. Did you end up trying a 45T in the rear and, if so, how did it work out for you?
It's generally not recommended to have one sprocket tooth count to be divisible by the other. 45 divisible by 15. Going to a 44 would be a better idea, at least for chain and sprocket wear.
A pretty good sprocket selector tool here:
Enter bike on top. Enter your desired sprocket sisez under current and or custom. Lots of good info. The chart on the bottom left shows number of chain revolutions between same tooth/link contacts, among other things. The higher these results are, the better chain wear you will have.
FWIW, I've put about 56k miles on my '15 and do not intend to stray from the stock ratio.
The best solution for jerkiness, that will actually work quite nicely, is the ECU re-flash from Shoodaben.
And yes, I ride the Versys quite briskly. I'm on my 13th rear tire, mostly quality sport touring tires, Angel GT, RSIII, Michelin PR4, T-31, T-023 and three short lived Shinko 705s(about 3500 miles). Favorites are RSIII and T-31.