You should save yourself alot of trouble and just go straight for the dual aileron servos. I have seen this problem in arfs and kits alike, and the usual contributing factor is substandard wood and clevises too close to the hinge line. Once you get flutter caused by this combo, the wood around the torque rods is ruined, and there is not much you can do without performing major surgery. Since you have an elaborate procedure ahead of you, why not go for the one which pays the most dividends in the end. You will end up with two servos and rock solid, worry free performance, or you could fix the torque rods, and wonder when it is going to happen again....