what would be wrong with building the end of the torque arm like Griggs does
http://www.howardweb.org/fastgt/docs/griggs_arm2.jpg http://www.griggsracing.com/images/MTA1000RST.jpg
it looks like the hole in the crossmember is a bit larger than the sleeve and that allows the torque arm to slide front to rear and side to side.
Would this have any downsides?