If the threads talked about ELO, they are outdated. The name Glicko(2) is used when talking about the new (Aug '18) rating system. The informations in OGS Ratings Revisited are outdated (not how glicko2 and our rating algorithm works by any means).
1 stone handicap is worth 1 rank. Black’s rank is adjusted for rating calculation. The ratings used are always the recent ratings. It doesn’t matter if a game was fair at any time. The (adjusted) rating difference leads to a prediction of how probable a win is (again using recent ratings). If the win is expected, the rating adjustment is minor, if it’s unexpected it’s big.