I will make a tool next time, if needed. When I did it I used an impact wrench, testing the diff gun settings on my truck lug nuts and seeing what the torque wrench said the torque was (approx for sure).
Then I used the closest setting to tighten the clutch nut.
You may find a socket to borrow at the auto parts store.
You may also cross ref it to an SAE size because it may be close enough. I believe 1 1/16 is the size I used but not 100% sure.
Harbor freight has some very large wrenches, metric, for about $40. Not sure if the size you need is in the kit. I just took my kit back because the wrenches were too wide for my ATV application.