I have found that a poor idle to max throttle response is most often caused by being to lean not being rich. What I have found to work when adjusting carb settings is to adjust the high end, then I bring the rpm's down to a lower range (1/3) throttle and adjust the low jet so the engine runs smooth, then check my throttle response. If I try to adjust the low end at idle it seems to cause problems in the low to mid range. After you get the low end set check your high end again, and repeat if need be. I use my throttle servo to set my idle.