I ALWAYS use a torque wrench on mine. Specially after its been to the dealer or the tire shop and they messed with them. I always find them torqued unevenly.
On my 2000 sierra i kept having warped rotors from just guessing. After i replaced the rotors and used a torque wrench all of those issues went away.
If you want a good torque wrench that isnt crazy money look into CDI Torque Products they make them for snapon at half the cost.I also have a huskey which i use often. Stay away from harbor frieght stuff. If it didnt need to be torqued to some specified requirement they wouldnt go to the trouble to list it. And your impact gun isnt going to cut it. Those just lead to over and uneven tightening, stripped threads, snapped off studs.
I do use a very long bar to loosen them though. I have a bad back so i need the extra leverage to undo them.
Never had a stripped,broken, or loose lug nut ever after buying and using the right tools. I know others will say its not needed but thats what I do.
on a 2000+ 1500 truck its 140ft/lbs im sure its different on the heavy duty.