I like the fact that the information theory adds up. To specify 30 bits he used a 26 bit number and then specified one of 24 permutaions, and this is just right because
Even if the number he specifies has leading zeroes, it's still one out of the set of 32 bit numbers.
Having leading zeros does make the length of the source code itself smaller though.
And this suggests a path for lowering the magic number. We can lower the number of bits needed by noting that the required outputs for 8 through 14 (mod 15) are the same as the outputs for 1 through 7 (mod 15), only reversed.