Your main controls the area of the throttle you were experiencing hesitation at... mine did the same thing, it is very common to see that on cubs. Never let a cub idle to long either because they like to load up and foul plugs, especially if your air screw and pilot are a little fat. 160's will do the trick by the way, atleast get you in the ballpark. Good luck...
Put those 160's in it, then find a place you can do a plug chop. That is pinned/sticky up top of this forum I believe.
Get the pilot and air screw jetted good out of the hole first before you begin messing with that main by the way. Should be 48-50 on the pilot, 3rd clip on your needle and 1-2 turns on the air screw. Get it to be nice and crisp off idle, then go do a plug chop and call it a day...