these use #2 as the set carb,,, adjust 1 and 2 together, using the screw on 1 , then 3 and 4, using the screw on 4, then bring them together using the screw on 2, only having a double gauge will see you doing the process several times to get it spot on,
I sync mine on at about 900 rpm, I found I got a much smoother finished job, than using a higher rev, as your going you might need to keep turning the idle down because the fueling is getting much closer to right