[kqr]

The observation that it is impossible to ennumerate 300 bits of assignments with a 256-bit random generator is a very clever observation. Just like almost all assignments are balanced (300 vs. 295 bits), I wonder if there's a similar equipartition property argument that 256 bits will generate the vast majority of the outcomes, but my Shannon-fu is too weak to tell.

Maybe that's the problem? With 256 bits we will only get the "typical" assignments and not the edge cases which are the ones that are important for randomisation tests?