Balling the end is correct, just make sure when grinding tungsten ANYTIME, not to use a contaminated wheel.
Welding up mild steel- sticking the tungsten- you stop and grind it so contamination doesn't effect the weld. Now,you weld for a while, an decide to ball the end for aluminum. If there was contam in the ground tungsten, it will still be present when you ball it. See what I mean. You need a separate wheel. My TIG instructor was a fanatic about it. You should see the way he "stacks coins." Try the smaller rod with the ball.
Another thing for nice welds- Be in a comfortable position,too. Vertical position welding doesn't look as good as horizontal.