Posting anonymously, but former CA3 clerk.
Grades-wise, it really varies, both by judge but also by year. If the clerks have the primary job of filtering out applications, their opinions on grades might become the judge's opinion.
That said: it was my impression that Krause, Shwartz, Chagares, and Barry (when she was active) had the most-stringent grade requirements. I actually was not aware of Hardiman's reputation for requiring tip-top grades; by contrast, it was my understanding that Smith was fairly demanding. Fuentes seemed to hire people who had been out in the world a little bit.