Yeah, I feel like randomness and "free will"-ness are pretty orthogonal. That said, I was able to keep the thing below a maximum of .56-ish without using any of the tricks others have suggested here, like picking an insignificant digit in the accuracy number and pressing 'f' or 'd' based on its value, or using the even/oddness of successive positions in π, or whatever.

So, apparently, my brain's PRNG is pretty random. But I still have absolutely fuck-all idea whether or not I have "free will".

Fun two-and-small-change minutes, though.