After drilling the antenna holes, the tip of the Sharpie is rotated near the edge.
TRIVIA: A 1/8" diameter launch lug actually has a 3/16" outside diameter.
The 1/2" support tube (with hardwood dowel interior) is slid into the 1/2" drilled hole.
The last Sharpie mark is the lug hole, running inside the ball along the side of the engine mount tube. It is 3" long and goes all the way through the ball.
As the sharpened 3/16" dowel is pressed through the ball, it is checked for straightness traveling along the inserted support tube in the ball.
Keep pressing and drilling until the sharpened end goes all the way through the top of the ball.
Keep your hand away from the top of the ball or your palm could be skewered!