I use a set of Hex sockets like this...


If thats not available you can get a M14x20mm bolt and over torque (or weld or locktite) the nut/nuts onto the bolt to create an adapter that fits in the wheel hex and you can then use a conventional 14mm socket on the torque wrench to adjust it.

Matt.

commercially available adapter too...although not the correct size but you get the idea?