I recieved my new Forster benchrest dies. The instructions for setting up the seating die seems pretty straight-forward. The sizing die though says to line up the hole in the die with the lower third of the ball expander. Question is.....how do I do this? The hole is much too small for seeing anything in there. How do you guys set these dies up? Meaning, how do you know that the ball expander is in it's proper position?