Holley Double Pumper Question(s)

Is there a decent parts diagram that can identify that rear set screw? I don’t know where or what screw that is.

Also the idle set screw doesn’t engage and there must be a reason. It is like it’s 3/8 too short but I know that it’s not. Does the carb need something to bring the idel set point farther up or something?
Look into the hole really good. A lot of them have the hole but it's not finished and drilled all the way through.