Urm cant recall perfectly, whole arm and fist is 1500tons without the body leaning in on him. To add to that it was moving at a fairly fast speed.
Thats true, then again he by that point he was near his ending strength. (already has upgrades to his DB and Yamato/DT) I'd say 80/90% max strength in that scene. Remember that after that fight all Nero does is fight Sanctus, get absorbed, run through Savior and fight Sanctus again. Then he's at end game strength.