Keep an eye on your tach and your drops if your kart is fast and free and you find yourself reaching for a 60 maybe or espesially a 59 or lower for rear to keep your Target RPM then bump your front to an 18 driver, If you would of needed a 17-59 so your gonna try the 18, I'd only jump 3 rear to a 62 track usually still gains a little or you hit tires better, If you feel Track is Done and your not gaining any then put a 64 rear with that 18.
I sure hope someone from track answers your question because without knowing the radius of the turns, or if there is banking. and how much, it's pretty hard, it seems to me, to give any kind of gearing recommendation. 17 60 is 3.51. Seems to me that's a big gear for that size track. Still, I don't really know so maybe I should just stay out of it.
I just hope someone from the track we're talking about can give you good advice.
Comments compliments criticisms and suggestions are always welcome.