Avoid using a shifter on adjusting nuts as this will wear the scale of your wrench. Use a 7/8" socket your wrench will love you for it, and last longer.
A very common complaint with industrial style torque wrenches is that the scale on the adjusting nut is very hard to see and inevitably results in replacement of the adjusting nut. The best way to adjust an industrial style Torque Wrench is with a socket on a ratchet, this way the scale remains like new. When a shifter or a spanner is used on the adjusting nut where the scale is, over time it wears the scale and makes it very hard to see the desired setting. Also, some adjusting nuts have a hole at the base of the nut. This hole should not be used to put a screwdriver in and turn the adjusting nut as it may damage the threads on the plunger rod and may make the wrench very hard to adjust. In this case, the wrench will require a new plunger rod and nut. The photos show examples of how to and how not to adjust your industrial type torque wrench.