Ray
It is a long time since I worked on a 7HA axle but from memory, I did not use a torque setting.
I screwed up the castellated nut until there was no play (in-out) in the hubs, and then backed off slightly to enable the split pin to fit. (good luck if you have wire wheel hubs, this job then becomes really fiddly!)
Then check that the backing off has not given rise to an unacceptable amount of play, if it has then file off the back of the nut to remove material and try again until you achieve a result that seems right. I also seem to remember that there was a fairly large washer behind the nut , you could try using a thinner (or thicker) one to achieve the same result.
Best to check the hub free play after a few miles to ensure that they are still set correctly.
