Simply memorize the contact points on the rail for a ball struck with medium speed at center ball on a line between any two diamonds.
This is not really as crazy as it sounds; because, symmetry reduces the number of distinct shots, many of the shots are easy to remember, and knowing only a subset of the shots helps immensly.
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If you do not reproduce the diagrams I am about to show you with the equipment you play on, simply change the diagrams to suit and remember that instead.