I wound up with flutter in my Tiger 2 also. The reason was that I didn't "harden" the wood that surrounds the torque tube with CA where it is inserted in the aileron. This was back in 1999 when I didn't know jack about such things. I suspect your slop is from the wood, not the torque tube iteself.

The real solution is to use separate aileron servos, as has been suggested.

Regards,
George