Stan and I disagree on hex bar vs. sync link, but here that really doesn't matter. Hex bars are sloppy unless modified with heim joints. I helped Lenny set up his sync link, and he is happy. I agree, it's a nice system.
Richard, you're going about this all wrong. Throw away the washers, they aren't helping you. Ok, you have sync at idle using the throttle stops. Great.
What you need to do is pull the throttle open very slightly, and hold rpm around 1500 to 2500. Even 3000 works, which is what I used to do. A hand throttle helps if you have one, I rigged one up. Doesn't matter much what rpm, just pick an rpm and STICK TO IT. Have a friend hold it there, using the throttle pedal, because that's how it will work when you're driving it. IMHO, 1500 is best as you want it perfectly synced just off idle, this is where your foot is when you are cruising down the road at 55-65.
Use the snail and the adjuster between the carbs to bring them as close as possible. It should be possible to get them spot-on. For reference, my synchrometer reads about 16-18 at this rpm. Take it for a drive, you're done. It is impossible to get them perfect at all rpm as Stan says. Idle and just off idle matter, once the plates are 1/4 open and beyond doesn't.