I've read your thread three times. Have you cleaned the throttle body passages while the carbs were off? Did you check the float bowls for warping? Many times the bowl is warped enough that the emulsion tube doesn't seal properly and a new bowl fixes the issue. Try replacing a couple of bowls,,when you do move the high speed orifice from the old bowl to the new replacement bowl. A gasket kit won't fix a warped bowl.