I guess there ain't much more you can do with a 1"1/8 steel ball and 2x 3"flipper bat's, 
What is the size of a pinball?
1 1/16" diameter, weight 80 grams for a regular steel ball.
1 1/16" diameter, weight 65 grams for the Powerball.
A "normal" pure ceramic Powerball would only weigh 40 grams. However, there
are apparently several different types of ceramic, and the Powerball is one
of these.
