Richard, close the air bleeds. Listen to Stan, he knows a thing or two. They are there merely to balance a low cylinder. This is maybe caused by a slightly bent or misaligned throttle shaft, maybe a throttle butterfly isn't 100% centered. Whatever, you bring the low cylinder up with the bypass screw. Once off idle, the bypass ceases to work. FYI, mine has one low and is balanced with the screw, the rest are closed.
Please, throw away the washers and the cut feeler gauge. Useless.
You need the airflow synchronized when you are driving, when you are pulling on the linkage with your right foot. PERIOD! Any other method is a fools game.
I am glad you figured out the difference L/R and didn't resort to swapping sides. But that is a good method for troubleshooting.