I think the above is a clear summary. The only thing I would add is the risk to taking 5700 or 9000 tickets. Taking 9000 tickets risks being left with 3000 unsold and presumably £75k out of pocket (or one weeks wages to a top earner?). Taking 5700 tickets risks 3000 fans being pissed off. I know...
More complicated this time. The clubs will be really uncertain as to how many of the 9k tickets we will actually sell. FA cup, 8pm Sat, on TV, no trains home make it very difficult to guess how many we will sell. Therefore they are only offering some blocks to start with.