the needle jet i was referring too is the brass tube that your main jet screws into. the size of this tube determines how much gas can get through the carb at idle. With more air flow it will pull more gas, but often (as you now know) its way to much. Most of the time this tube is a size 2.22, if you make the tube smaller (like a 2.17 or a 2.20) then you are reducing the amount of gas you will get at idle.
The clip that you are talking about determines how much gas your are getting from 1/4 throttle until 3/4 throttle. At WOT the needle is no longer a factor and only main jet size determines rich or lean.