Over tightening the spindle nut will lead to premature bearing failure. Here is how I do mine.
1) pack bearings
2) place hub on spindle and rotate hub at the same time tighten nut hand tight
3) Back off and retighten to finger tight while spinning until a slight drag is felt.
4) Back off to line up cotter pin.
There will be some play from .001 to .010 to allow for heat expansion as the wheel rolls.
Note how at no time I said use a wrench or socket. The nut should never be more than finger tight at most.