do a search on 17s i think that they are humanly possible but only after the rubber has been slashed away that prootects the SA. all husaberg sprockets are interchangable.
best gearing is validated by your rev counter and the speedo. i don't think anyone here has ever claimed to have the best set up because it depends whether your bike is tuned, you wore leathers, prone or upright. etc etc.
don't make the mistake of highest RPM = top speed. it often isn't, especially on a torquey single. by flicking between revs and highest speeds you'll be able to gather where it's at it's fastest. would suggest (and plenty of SM riders here will beat me up if i'm wrong) but you're best having gearing that allows "flat out crazy MF in 5th gear" and 6th is for cruising and saving the engine.
you can tell from this site just how frail these engines can be - your only so far from the big bang theory!
suggest that at the end of the day it will be sheer wind resistance that beats you!
regards
Taffy