Try installing a thin card board gasket under one of the carbs to isolate it. Don't cut the center hole, make sure it's solid. Get one carb where it will idle and run, then do the other one the same way. If you set the idle speed the same on each one, it should be close with both running together. You will still need to tune once both are running so turn each screw the same on both units till you get it squared away. A Uni-syn ( http://www.speedwaymotors.com/Uni-Syn-Carb-Synchronizing-Tool,267.html ) would really help you.
Double check for vacuum leaks at the intake to head area and under each carb. If the engine was running before you started this, timing should be close enough to run now.
Whats it take to get it restarted?
Joe
