Assuming you have the socket and perhaps a torque wrench you can improvise by using an extender bar.
The info is in a snap-on booklet that I have someplace.
Simple explanation is that if you double the grip length you double the torque reading.
For a 1/2" torque you could use a 1/2" spanner as your extension.(you would need the spanner to be as long as the torque wrench to be accurate or calculate the ratio))
Another economical possibility would be the torque bars drives that the tire shops use to mount rims.
These are generally color coded about 6" long and simply are installed between the wheel nut and the impact gun.
I think they work based on the temper of the steel shank.
If it were me, and providing you had a pneumatic impact air driver, I'd simply fire up the impact and drive the nut on until it stopped turning just like the shops when they install your tires. Ever notice you cannot undo those lug nuts?
On that mower, the shafts and nuts will be graded steel so you won't strip them. Just use a new lock nut every time if one was originally there.
Like always be sure the threads are clean and drive them dry, no lube.
Just my opinion. (but then I was a licensed aircraft mechanic)
