Salisbury Axle backlash/preload help

Evening all,

Just looking for a bit of advice on a check I would like to do to my axle please. Changed the flange seal yesterday and I'm worried I've not done the nut back to the place it was already at. I have to remove the rear cover as that is leaking anyway, what do I need to do to check the flange bolt is tightened correctly?

Thanks in advance!

Can’t help with preload etc but have a look at Mikes videos on YouTube, Brittanica restorations, he’s done a few axles and one was definitely a Salisbury.