did you try plugging one of your 3114s into your gyro or ch4? sometimes a bad servo will cause jittering...i recommend that you have a spare servo on hand to trouble-shoot problems like this...btw, a simple and basic test of tail effectiveness is to turn the nose of the heli to the left...when you do that, the tail pushrod should move forward...with a heading hold gyro, the leading edge of the tail blades will move toward the boom and stay there...ken