/64 and /48 are pretty much on the same order of magnitude as IPv4s in terms of difficulty of acquisition, and I don't know why you would ever look at more than

/64 and /48 are pretty much on the same order of magnitude as IPv4s in terms of difficulty of acquisition, and I don't know why you would ever look at more than /64 when most major operating systems randomize the last 64 bits anyway (RFC4941).