This is what i bought back in 2012 and it works great ! You can dial in the belt tension and torque the axle nut with no movement in the adjustment.

 

I've used the 3rd hand tool 3 times now and it works PERFECT!

 

I just borrowed a pair of 23mm (I think) sockets when I did mine. Torque wrench on one side and breaker bar on the other. Took a couple of tries to do it without moving the adjusting cam while tightening but managed to figure it out.

 

I use the second wrench arrangement and put a bottle jack under the far end of the wrench on the side that needs to be held. The bottle jack is infinitely adjustable. Don't know how expensive the tool is, but this is free" with what I had on hand.

 

The nice thing about the 3rd hand tool, combined with a torque adapter, no need to remove exhaust components for a simple belt adjustment/axle torque.