The No2 carb is the biggest problem in adjusting. I got a small flat driver from my socket screw driver and fitted a short piece of plastic Tube to the flat end this holds it on the screw and then a longer piece of hose to the other end so you can turn it with your hand. It's still not easy to turn and watch at the same time to see how far you have turned it. I got big hands and its herd to get one in there.
I would be interested in knowing how others get around this.