Two questions regarding $50nl hu tables on pokerstars

[TNixon]

I've heard numbers anywhere from 6ptbb/100 to 10ptbb/100 being presented as "good" winrates, in much the same way that a 60% winrate is presented as "good" for HUSNGs. (where in reality, 60% is *extremely* good. Definitely achievable, but not likely, for a majority of players)

I have no clue if those are actually realistically and consistently possible, or if people just pull numbers out of their ass, or if those winrates are generally at higher levels, though.