That's pretty much the way I do it. I tighten the nut while turning the hub till it is tight enough that it hard to turn, then I loosen the nut while still turning the nut till it turns freely. As soon as it turns freely, I put the cotter key in the nearest flat.
If you want to put some numbers to that, many years ago, I used a beam torque wrench while tightening. It would usually get tight around 10 ft-lbs more or less, probably less. You want to make sure the bearings are fully seated on their races before loosening the nut.
Other people may have their own methods, but that's mine and it seems to work for me.
