Tighten with a wrench "moderately " tight, tight as you can with one hand not stand on the wrench with all your weight tight. Loosen until you can move the nut with your fingers, then take a thumb and forefinger (same hand) and snug it as tight as you can. You're done, lock it. With a gauge is more work and doesn't work any better than the finger method. I did one side of my 300sd one way and other side the other way years ago. No difference. Never used the gauge again. Lot of shops use the finger method on MBs and all cars and don't have any return complaints.

__________________
85 300 SD ~ 115K
82 500 SEC Euro ??K
78 450SL 164K