Just jump straight two sizes up around 180. Get a range of 145 to 170. Also possibly order a 130 or 135. My Athena ran as low as a 125 quite well, while my LC scooter cylinder on the same intake setup is happy at a 165 but ran well between 140-165 with little noticeable difference.
I also found that the pilot jet was too large stock at 15. I currently am running a 10 very well. The bike still ran okay but if I let it idle for long enough when hot it would load up and begin to die unless I cleared out with some throttle. Also the idle air screw adjustments were vague at best. once the pilot jet is size right you should notice a difference in mixture with as little as a quarter turn.