With the punch/threaded-rod/screwdriver technique to remove the cups, be sure to alternate back and forth to opposite sides so you don't angle the cup.

Good trick to get the crown-race back on is to use an adjustable crescent-wrench. Put the jaws on both sides of the steerer, tighten the wrench so it's snug, slide down onto the crown-race. Tap with hammer on the sliding mechanism that joins the two jaws and you'll be able to apply force on opposite sides of the race evenly.