I think what they are trying to say is if you block off an air bleed and the the idle increases then it is a lean condition. When you block off an air bleed you enrichen the mixture so it is lean? I would start with the outboard idle screws out 5/8 turn from seated and go from there. Then tune the outer carb since you can get at the screws with it on the engine and then switch it with the back one and adjust it while running.