If it’s a 5 point race, when is it called?
Not until the metro counties have reported a significant chunk of their votes. Maybe 10:30 or 11?
Polls close at 8?
If the law is the same as for GEs, they will close at 7 pm ET. FWIW Georgia now counts the early vote first, then the election day vote, and finally the later received mail-in ballots. This means that it should start off very Dem-leaning, then swing very R, and then swing back toward Dems at the end.
Hopefully the call from NBC/MSNBC at poll closing will be too early to call, but Warnock is in the lead.