Lets use 20 mA x 64 LED as an example. Assuming its running on 5v, using constant current driver to sink, (that sounds like the direction he is heading), it should use up to 1.28A. With this design, he is only doing 12.5% duty cycle. How do we apply the math to figure out what specific specifications to look for, and ranges maybe? It seems like a simple table would be easy enough to make.