@Mark-Touch
If your BU is not used, and most of the time she's not, you can certainly use her in a later round as your main pick.
High-point tourneys have more rounds than lower-point tourneys. We don't play 250s, and select from 500s, 1000s, all the Grand Slam events, plus Olympics.
You try to win one round after another to get into the final, and must win that final round, to be a champion. (Last year we had five champions in this tourney.) There's no play-off in the tourney after that. We fall by the wayside whenever our pick loses - sudden death. If we keep winning, proceeding through all the rounds, we take our trophy and run (after our on-court interview, thanking the crowd, sponsors, coaches, etc.)
You are credited with the points you win per tourney in the Google sheets, accessible by pressing the blue "League File" link near the OP beginning. On those sheets you will see that, like "real" players, we have a Ranking points list (points accumulated in last 12 months) and a Race points list (points won so far in the present season).
Of interest are the tabs at the bottom of the Google sheets. Click in, to find information about the season schedule, past champions, and more.
(Btw, Hsieh's been off the boil a while...sad to see. Maybe Mertens isn't the best fit for her after all?)