The polini is basically bolt on and go. It's very forgiving.
Upjet till it four strokes, then go down one.
Idle jet bogs at take off or mid throttle, go up. (Usually. Sometimes they do the same thing whether rich or lean.) If the screw is out more than 2 turns and your idle is still rising, bigger jet. If it's screwed all the way in and nothing happens, smaller.
Needle isn't do much besides control idle on a polini, and I haven't had to change one yet, all my lips are in the middle.
If nothing works, the carb probably isn't the problem. Air leaks, head gasket leak, plug too cold, etc.