I just discovered that the open post/cut and fill offense is very similar, if not identical, to the Read and React Layer 1, 5 out motion (although layer 1 can also be used for a 3 or 4 out motion). There are some Read and React Layer 1 videos available on the Net which show a good demonstrations of what the open post offense should like like. They use the 3 point line as the read spot. These are very helpful and informative to watch.